How Much Do You Really Need to Retire in Singapore?

Retirement planning isn’t just a financial milestone — it’s the foundation of future financial independence. In Singapore, where life expectancy now averages around 83.5 years and the official retirement age is rising to 65 by 2030, the period you need to fund can span 20–30 years after work stops.

Most professionals recognise when they want to stop working, but far fewer understand how much they’ll need to sustain their lifestyle for decades beyond that point. This gap in understanding often leads to under-saving, especially when inflation, healthcare costs, and lifestyle expectations are taken into account.

In simple terms, your retirement number should reflect:

1. Your desired retirement lifestyle — from basic living to comfortable or aspirational spending.
2. Duration of retirement — how many years of income you need based on life expectancy and planned retirement age.
3. Your income replacement strategy — how much of your pre-retirement income needs to be replaced by CPF, investments, and savings.

Singapore’s unique retirement system — centred on the Central Provident Fund (CPF) and complemented by tools like the Supplementary Retirement Scheme (SRS) — means that planning for retirement is both structural and personalised. 

Whether you depend mainly on CPF LIFE payouts or supplement them with personal investments, a clear calculation of your retirement needs is essential to avoid running short or over-accumulating unnecessarily.

This guide distils best practices and up-to-date data into a step-by-step framework that helps you not just estimate a retirement number, but plan for it — drawing on CPF projections, spending benchmarks, and investment principles that can help you make your retirement vision a financial reality.

Step 1: Decide when and how long you will be retired

A retirement plan is only as accurate as the assumptions behind it, and the most important assumption is the length of time your savings need to last. 

In Singapore, this duration has been shifting because of structural trends: rising life expectancy, later statutory retirement ages, changing employment patterns, and evolving expectations around work and lifestyle.

Determining your retirement age and planning horizon sets the foundation for every calculation that follows. It determines how much you need to save each year, how aggressively you need to invest, and how much income you can sustainably withdraw later on.

1.1 Singapore’s retirement and re-employment ages are evolving

Singapore’s official work-age thresholds have been rising over time. These changes are not cosmetic; they reflect long-term demographic and economic realities.

Current policy trajectory:

• The statutory retirement age is 63 today and will rise to 65 by 2030
• The re-employment age is 68 today and will rise to 70 by 2030

These shifts are driven by structural forces:

• People are living healthier for longer, extending their productive working years
• Firms are adapting to an ageing workforce by redesigning roles and retirement expectations
• Longer life expectancy requires longer periods of income security

For your retirement plan, these ages should be used as signals, not endpoints. You should consider:

• Whether you intend to retire earlier than national norms
• Whether you prefer a phased transition into part-time or advisory work
• Whether your lifestyle goals require an extended or shortened career

The decision you make here influences everything downstream, including CPF drawdown timelines, investment horizons, and your ability to accumulate enough capital before your first withdrawal.

1.2 Longer life expectancy means more years to fund

Singapore’s life expectancy is among the highest in the world, and it continues to rise. This trend has profound implications for retirement planning.

Key figures:

• Life expectancy at birth is around 83.5 years
• A 60-year-old today can expect roughly 24 more years of life on average
• A meaningful proportion of people will live well into their 90s

This lengthens the retirement period across generations. Based on current trends, a realistic financial planning horizon looks like this:

• If you retire at 65 → plan for 20 to 25 years
• If you retire at 62 → plan for 23 to 28 years
• If you retire at 55 → plan for 30 to 35 years or more

Several factors make longevity risk more important today:

• Improvements in healthcare and medical technology are extending the average lifespan
• Chronic conditions can stretch healthcare and living expenses across more years
• Families are smaller, meaning fewer dependents to share eldercare responsibilities
• Inflation compounds over extended retirement periods, eroding purchasing power if not properly accounted for

Ignoring longevity risk is one of the most common reasons retirees deplete their savings too quickly. Planning for a longer retirement horizon is now a necessity, not a conservative assumption.

1.3 Why retirement duration is a critical input

The number of years you expect to be retired is not just a planning detail. It is one of the most sensitive variables in determining how much you ultimately need.

Retirement duration directly affects:

• Your required lump sum: extending your retirement horizon by 10 years can increase the required portfolio by 40 to 70 percent, depending on inflation
• Your withdrawal rate: a 4 percent withdrawal rate may be sustainable for a 25- to 30-year retirement, but not for a 35-year retirement
• Your investment strategy: a longer retirement shifts the portfolio toward growth assets to maintain purchasing power
• Your reliance on CPF LIFE: CPF LIFE provides longevity insurance, but its payouts must be evaluated against a longer lifespan
• Your probability of shortfall: the longer the horizon, the greater the risk of outliving savings unless appropriately planned

In short, defining your retirement age and planning horizon is not a formality. It is the anchor of your retirement strategy. Every subsequent calculation—monthly budget, inflation adjustments, CPF adequacy, and investment needs—depends on getting this assumption right.

Step 2: Define your retirement lifestyle and monthly budget

To estimate how much you will need in retirement, you must first understand the lifestyle you want to maintain. The most reliable way to do this is to anchor your expectations to spending profiles that reflect how Singaporeans actually live in retirement today.

A recent nationwide study by OCBC highlighted three lifestyle tiers that Singaporeans tend to fall into. These categories offer realistic estimates of what different levels of comfort cost, and they provide a strong foundation for calculating your long-term financial needs.

2.1 Dissecting realistic lifestyle tiers 

According to recent findings, retirees typically align with one of three lifestyle profiles:

Basic lifestyle

• Estimated spending: around S$2,700 per month per person

Comfortable lifestyle

• Estimated spending: around S$3,400 per month per person

Aspirational lifestyle

• Estimated spending: around S$6,100 per month per person

These figures are not theoretical—they mirror how different groups of Singaporeans envision and fund their retirement lifestyles.

Notably, the same study found that 63% of people in their 60s prefer the basic lifestyle, even though a significant proportion tend to underestimate how much it actually costs.

2.2 Refine the numbers based on your personal circumstances

While these lifestyle tiers provide a solid starting point, you should refine the estimates by examining your own expected expenses:

• housing: fully paid HDB, private property, or ongoing mortgage
• healthcare: subsidised clinics versus private specialists; rising medical needs
• transport: public transport, private hire usage, or car ownership
• dining and groceries: home-cooked meals versus regular dining out
• travel: type and frequency of holidays
• domestic help: none, part-time, or full-time
• family support: contributions to dependants or shared expenses

These adjustments may shift your actual spending slightly above or below the benchmark of the lifestyle tier you choose.

2.3 Why this step influences your entire retirement plan

Your monthly spending assumption feeds directly into:

• the size of your total retirement portfolio
• how much CPF LIFE may or may not cover
• your required savings rate during your working years
• your sustainable withdrawal rate
• the buffer you need for unexpected expenses

Small changes compound meaningfully. For example, increasing your expected monthly budget by S$500 results in an additional S$150,000 to S$200,000 of required savings over a typical 25–30 year retirement.

Setting your lifestyle assumption accurately is one of the most important steps in determining how much you need—and in building a retirement plan that realistically matches the life you want to live.

Step 3: Account for inflation and how it compounds over time

Inflation is one of the most important variables in retirement planning. It determines how much your lifestyle will cost in the future and directly affects the size of the portfolio you need. 

3.1 Singapore’s inflation trends: what the long-term data shows

Singapore’s inflation environment has normalised after the spike in 2022–2023, but the price level remains structurally higher.

Average annual inflation rates (Singapore):

Inflation at these levels may seem mild year to year, but their long-term effects on retirement planning are substantial.

3.2 Healthcare inflation typically rises faster than general inflation

Healthcare costs rise much faster than general inflation and should be modelled separately in any retirement plan.

Over the past 20 years, medical and dental treatment costs have increased by about 78%, equivalent to 2.9% per year—almost double Singapore’s long-term core inflation rate of roughly 1.5%.

More importantly, short-term projections show a sharp acceleration. Medical cost inflation is expected to reach 12.3% in 2024, 15.5% in 2025, and 16.9% in 2026, well above regional averages.

Why healthcare inflation is structurally higher

• rising incidence and earlier detection of chronic conditions (cancer, diabetes, cardiovascular disease)
• ageing demographics increasing demand for long-term and specialist care
• rapid adoption of new medical technologies and treatments
• higher pharmaceutical and diagnostic costs
• healthcare workforce shortages driving wage and operating cost pressures
• higher utilisation of private healthcare services
• more complex disease profiles across age groups, especially among those under 40

Given these drivers, healthcare inflation should be assumed to run meaningfully higher than general inflation, and it will form an increasing share of retirement spending over time.

3.3 How inflation reshapes your retirement lifestyle cost

A lifestyle that costs S$2,700, S$3,400, or S$6,100 today will not cost the same in 10, 20, or 30 years. Even at a moderate annual inflation rate of 2.5%, prices compound quickly over time.

The earlier you retire, the stronger the compounding effect because inflation acts on your spending across more years before and during retirement.

3.4 Inflation affects some categories more than others

Inflation does not impact all components of a retirement budget equally.

Categories that tend to rise faster:

• Healthcare and chronic care
• Caregiving or domestic helper costs
• Travel and leisure (sensitive to currency and global demand)
• Food and dining (affected by wage pressures)

Categories with more stable inflation:

• Utilities and household essentials
• Basic public transport
• Subscription-based services

This makes it important to budget higher inflation assumptions for medical and caregiving needs, as these categories often account for a significant portion of retirement spending later in life.

3.5 Why an inflation-adjusted budget is essential

Accounting for inflation isn’t just a technical step — it is the factor that keeps your retirement plan grounded in reality. An inflation-adjusted lifestyle cost directly determines:

• The portfolio size needed at retirement
• How much of your income CPF LIFE can reasonably cover
• The savings rate required during your working years
• Your sustainable withdrawal rate
• The buffer needed for unexpected expenses

Planning in “today’s dollars” helps with intuition, but your investment and savings targets must be built in future dollars, where decades of compounded inflation create a very different financial environment.

A robust retirement plan anticipates this and ensures your future lifestyle is protected from the gradual, persistent rise in prices over time.

Step 4: Calculate your retirement number

Once you know your lifestyle cost and how inflation will reshape it over time, you can translate these figures into a realistic retirement number. This number represents the total portfolio value you need at retirement to sustainably fund your lifestyle across 20 to 30 years.

There are three practical ways to calculate this number. While they differ in methodology, they converge toward a similar outcome when applied correctly.

4.1 Method 1: Annual expenses × years in retirement

This method multiplies your future yearly lifestyle cost by the number of years you expect to be retired. It is intuitive and works well as a baseline.

Formula: Annual retirement expenses × number of years in retirement

Example using a future lifestyle cost of S$5,580/month (inflated 20-year version of S$3,400):

• Annual expenses: S$66,960
• If retired for 25 years: S$66,960 × 25 = ~S$1.67 million

This approach is simple but does not account for investment returns during retirement.

4.2 Method 2: Income replacement ratio

This method assumes retirees need around 60% to 75% of their last drawn income to maintain their lifestyle, since some expenses decrease over time.

Formula:last drawn annual income × 60–75% × years in retirement

Example:

• Last drawn income: S$8,000/month
• Replacement ratio: 70%
• Required annual income: S$67,200
• Over 25 years: ~S$1.68 million

This is useful if your lifestyle closely aligns with your current income level.

4.3 Method 3: The 25× rule (4% safe withdrawal rate)

This method estimates the portfolio needed to withdraw 4% annually (inflation-adjusted) without running out of money over 25–30 years.

Formula: annual expenses × 25 = required portfolio

Using a 20-year inflation-adjusted lifestyle cost of S$5,580/month:

• annual expenses: S$66,960
• portfolio needed: ~S$1.67 million

This aligns closely with the first two methods when inflation is factored in.

4.4 Comparing the three methods

All three methods converge to a similar estimate when calculated properly.

Example for someone retiring in 20 years with a S$3,400 lifestyle today:

This triangulation gives you a defensible, realistic target.

4.5 How CPF LIFE fits into your retirement number

Your investment portfolio does not need to cover your full lifestyle cost. Part of your income will come from CPF LIFE payouts, which vary depending on your Retirement Sum at age 55.

CPF LIFE typically covers 20% to 50% of a middle-income retiree’s spending, depending on lifestyle and inflation-adjusted needs.

Your personalised retirement number becomes:

inflation-adjusted retirement need – projected CPF LIFE payouts = required investment portfolio

This is the capital you must build through CPF SA/RA top-ups, SRS contributions, and personal investments.

4.6 Bringing everything together

To calculate your retirement number:

1. Define your retirement lifestyle cost
2. Adjust it for inflation based on your retirement timeline
3. Convert your monthly future cost into an annual figure
4. Apply either the 25× rule or multiply by years in retirement
5. Subtract CPF LIFE’s projected payouts
6. The remainder is the portfolio you need to build

Step 5: Understand CPF interest rates and CPF LIFE

Your CPF savings form the foundation of your retirement income. Knowing how CPF grows — and how CPF LIFE converts this into lifelong payouts — helps you reduce the size of the investment portfolio you need to build on your own.

CPF pays some of the highest risk-free returns available in Singapore.

• OA earns a minimum of 2.5% p.a. (pegged to bank deposit rates, with a legislated floor)
• SA, MA, RA earn a minimum of 4.0% p.a. (10Y SGS yield +1%, with a 4% floor extended through 2026)

Extra interest boosts returns further:

• Below age 55 → +1% on the first S$60,000
• Age 55 and above → +2% on the first S$30,000, and +1% on the next S$30,000

This means part of your CPF can earn up to 6% p.a., fully guaranteed.

Source: CPF

5.2 How CPF interest compounds your savings

CPF interest compounds quarterly.

Because SA and RA grow at 4%+ with extra interest from age 55, your Retirement Account can grow meaningfully in the 10–15 years leading up to CPF LIFE payouts.

This compounding reduces the reliance on your personal investments to fund retirement.

5.3 CPF LIFE: your lifelong payout stream

CPF LIFE converts your RA balance at 65 into guaranteed lifelong income, protecting you from outliving your savings.

Payouts depend on:

• Your RA balance (BRS / FRS / ERS)
• Your chosen plan (Standard, Escalating, Basic)

CPF LIFE typically covers 20% to 50% of a middle-income retiree’s lifestyle needs.

5.4 How CPF fits into your retirement number

CPF reduces the amount your personal portfolio must fund.

To integrate CPF:

1. Project your CPF balances to age 55 using OA 2.5% and SA/RA 4%+
2. Convert your RA balance into CPF LIFE payout estimates
3. Subtract CPF LIFE payouts from your inflation-adjusted lifestyle cost
4. The remainder is what your investment portfolio must generate

CPF’s guaranteed returns and lifetime payouts make it your retirement “income floor”, while your investments provide flexibility and lifestyle uplift.

Step 6: Integrate healthcare and long-term care into your retirement plan

Healthcare is one of the most important components of retirement planning in Singapore. It is also the category with the fastest cost escalation. 

6.1 Healthcare costs rise with age and are more volatile than general expenses

Healthcare demand naturally increases as you enter your 60s and beyond — through more frequent consultations, diagnostics, medications, and treatment of chronic conditions.

At the same time, healthcare inflation is structurally higher than general inflation, so medical and caregiving costs tend to grow faster than other lifestyle categories. 

For this reason, it is prudent to budget a separate and slightly higher inflation rate for healthcare instead of applying a flat rate across all expenses.

6.2 Understand what insurance actually covers

Singapore’s healthcare financing ecosystem includes multiple layers of protection — some are automatic, others optional — and each plays a different role in reducing out-of-pocket risk during retirement.

Government-mandated health coverage (basic hospitalisation)

• MediShield Life provides lifelong coverage for large hospital bills and selected costly outpatient treatments, regardless of age or health status. It is universal for citizens and permanent residents, and premiums can be paid with MediSave. 

Optional enhancement for broader medical coverage

• Integrated shield plans (IPs) top up MediShield Life with additional private insurance benefits, offering higher claim limits and coverage for private or higher-class wards.

Critical illness and related insurance

• Critical illness policies pay a lump sum on diagnosis of covered serious conditions like heart attack, stroke, or major cancer, helping with treatment costs or income replacement.
• Cancer-specific plans focus on oncology treatments across stages and may be more cost-efficient for those with family history or higher risk. 

Long-term care protection

• CareShield Life (and its predecessor ElderShield) provides monthly payouts for severe disability or long-term care needs, helping cover ongoing support if activities of daily living become difficult. 

6.4 Plan for long-term care, not just hospital bills

Retirement healthcare planning must include long-term care needs such as:

• Assisted daily living
• Home nursing
• Day activity centres
• Long-term caregiving support
• Potential need for part-time or full-time helpers

These costs can exceed typical hospital bills because they are recurring, long-duration expenses.

CareShield Life provides monthly payouts for severe disability, but it may not cover the full cost of long-term care, especially if private services or round-the-clock assistance is required.

6.5 Build a healthcare buffer into your retirement budget

To avoid underestimating medical needs, incorporate:

• A higher inflation rate for healthcare (e.g., 3–5% long-term baseline)
• An annual medical allowance separate from lifestyle spending
• A long-term care provision for your late 70s, 80s, and beyond
• A reserve for large, unexpected medical events

A practical approach is to add 10–20% to your annual retirement budget specifically for medical and long-term care expenses, adjusting further based on your health, family history, and insurance coverage.

Step 7: Savings and investment strategies to reach your retirement number

Once you know your retirement target and how much CPF LIFE will cover, the next step is to build a savings and investment strategy that closes the gap. 

7.1 Start by defining your contribution rate

Your retirement strategy begins with how much you can consistently save. A useful rule of thumb:

• Saving 15–25% of income is generally sufficient for those starting in their late 20s or early 30s
• Saving 25–35% may be necessary for those starting in their 40s
• Those aiming to retire early often save 40% or more

The earlier you start, the more compounding does the heavy lifting.

7.2 Optimise CPF top-ups for guaranteed returns

CPF is one of the most effective tools for long-term compounding due to its stable, risk-free interest rates.

You can boost your retirement readiness by:

• Making voluntary contributions to your CPF Special Account (SA)
• Using the Retirement Sum Topping-Up Scheme (RSTU) to top up your SA (or RA after 55)
• Taking advantage of tax relief for eligible SA or RA top-ups
• Letting SA and RA balances grow at 4%+ with extra interest

These top-ups are especially powerful for individuals who prefer lower-risk growth or want a guaranteed income base through CPF LIFE.

7.3 Use the Supplementary Retirement Scheme (SRS) for tax-efficient investing

The SRS offers additional tax benefits and investment flexibility.

Key advantages:

• Contributions reduce chargeable income
• Invested amounts can grow tax-deferred
• Only 50% of withdrawals are taxable at retirement (from age 63 onwards)
• A wide range of investment options, including ETFs, unit trusts, and bonds

SRS is most effective for those in higher tax brackets or those looking to diversify beyond CPF’s constraints.

7.4 Build a diversified investment portfolio to drive long-term growth

While CPF provides guaranteed returns, it typically cannot cover higher-cost or aspirational lifestyles on its own. This is where market-based investing fills the gap.

A robust portfolio should:

• Combine global equities, bonds, and alternative asset classes
• Be diversified across geographies, sectors, and risk factors
• Align risk exposure with your time horizon
• Rebalance periodically to maintain your intended allocation

Historically, diversified global portfolios have delivered 5–7% annual returns over long horizons, making them well-suited for building wealth for retirement.

7.5 Adjust your portfolio risk based on your timeline

Your risk level should evolve as your retirement approaches.

General guidelines:

• 20+ years from retirement: Prioritise growth; higher equity allocation
• 10–20 years: Maintain balanced exposure; begin managing downside risks
• <10 years: Gradually reduce volatility; tighten allocation to income and stability
• During retirement: Adopt a sustainable withdrawal strategy and avoid excessive concentration

This progression ensures your portfolio grows during your accumulation years and stays resilient during your drawdown years.

7.6 Maintain a sustainable withdrawal strategy in retirement

Once you retire, how you withdraw your funds matters as much as how you invested them.

Common frameworks include:

• The 4% rule, adjusted annually for inflation
• Dynamic withdrawal rules based on market conditions
• Bucketing strategies that separate near-term cash needs from longer-term investments

Your retirement budget, inflation, and health needs all factor into choosing the right withdrawal method.

7.7 Bring CPF, SRS, and investing into a cohesive plan

A strong retirement strategy in Singapore typically includes:

• CPF SA/RA compounding at 4%+
• CPF LIFE providing the lifelong income floor
• SRS offering tax-efficient investment growth
• A market-based portfolio delivering long-term returns
• Insurance to protect against major healthcare and long-term care risks

Together, these elements provide a durable, multi-layered structure for achieving your retirement number.

Step 8: Build your retirement roadmap

A retirement plan becomes actionable when it is broken down into clear steps. With your retirement number, CPF strategy, and investment approach defined, your final task is to build a structured roadmap you can follow and adjust over time.

8.1 Set clear financial milestones by age

Milestones help you stay accountable and track your progress. As a guideline:

• By age 30: establish emergency savings, begin CPF top-ups, and start long-term investing
• By age 40: accumulate at least 2–3× annual income in investable assets
• By age 50: reach 4–6× annual income, depending on lifestyle goals and retirement age
• By age 55: understand your CPF Retirement Account balance (BRS/FRS/ERS) and how it translates into CPF LIFE payouts
• By age 65: shift to a sustainable withdrawal and healthcare funding strategy

These benchmarks can be adjusted based on income, career trajectory, or desired retirement lifestyle.

8.2 Automate contributions to ensure consistency

Consistency matters more than size when saving for retirement. Automate:

• Monthly investments into diversified portfolios
• CPF SA or RA top-ups (where applicable)
• SRS contributions for tax efficiency
• Insurance premium payments to ensure continuous coverage

Automation reduces the reliance on discipline and helps smooth out market timing risk.

8.3 Review your plan annually and adjust for changes

Retirement planning is dynamic. Revisit your plan at least once a year to update:

• Your expected retirement age
• Lifestyle spending assumptions
• Inflation expectations
• Insurance coverage
• CPF LIFE payout projections
• Portfolio performance and risk levels

Small adjustments help you remain on track even when circumstances change.

8.4 Build buffers for uncertainty

A robust retirement plan should prepare for variables you cannot fully control.

Useful buffers include:

• A 10–20% lifestyle buffer for medical or long-term care
• Higher-than-expected inflation scenarios
• Market downturns during early retirement (sequence-of-returns risk)
• Unexpected family-related expenses
• Longevity risk if you live well past your expected lifespan

These buffers ensure your plan remains resilient across economic cycles and personal circumstances.

8.5 Keep cash reserves for short-term needs

During retirement, maintaining a cash or near-cash reserve for 1–2 years of spending reduces the need to withdraw from investments during market downturns. This stabilises your portfolio and extends its longevity.

8.6 Align your roadmap with your long-term lifestyle vision

Your retirement plan should support the life you want to live — not the other way around. Revisit your lifestyle assumptions periodically:

• The type of home you wish to live in
• How often you plan to travel
• Your long-term health needs
• Preferred activities, interests, and commitments
• Family support expectations

A clear vision ensures your roadmap remains meaningful and personalised.

8.7 Use CPF LIFE as your income floor and investments for lifestyle flexibility

CPF LIFE provides stability by covering essential expenses. Your investment portfolio should support:

• Discretionary lifestyle spending
• Travel
• Healthcare and caregiving
• Major unpredictables

This balance gives you peace of mind while preserving financial flexibility.

Conclusion: How much you need to retire in Singapore

Retirement planning ultimately comes down to one question: how much do you need in total?

The answer depends on three variables:

1. Your desired retirement lifestyle
2. How many years you are from retirement (inflation runway)
3. How many years you will spend in retirement (funding horizon)

By combining lifestyle costs, inflation, and retirement duration, we can estimate realistic ranges for Singapore.

9.1 if you are 10 years from retirement

(Assuming retirement at 65 and inflation of ~2.5% per year)

9.2 if you are 20 years from retirement

(Prices rise ~64% over 20 years)

9.3 if you are 30 years from retirement

(Prices roughly double over 30 years)

(Ranges reflect different withdrawal strategies, portfolio returns, and buffer requirements.)

9.4 interpreting the ranges

• If your lifestyle today is around S$2.7k, your future retirement target will likely fall between S$1.0m and S$2.2m, depending on when you retire.
• If your lifestyle is closer to S$3.4k, you will need S$1.3m to S$2.3m.
• If you aim for a more aspirational lifestyle at S$6.1k, expect a target in the S$2.3m to S$3.9m range.

These numbers represent the total portfolio needed before subtracting CPF LIFE payouts. Once CPF LIFE is accounted for, the required investment portfolio becomes significantly smaller.

9.5 the bottom line

• The farther you are from retirement, the more inflation reshapes your number
• The longer you remain retired, the more capital you need to sustain withdrawals
• Your lifestyle choice is the single biggest driver of your final retirement number

The earlier you define your lifestyle, calculate your inflation-adjusted future budget, and map out your funding horizon, the more accurately you can target your retirement number — and build the plan to reach it.