Finance calculator

Free savings distribution calculator

See how long your savings will last with regular withdrawals — enter balance, annual return, and monthly withdrawal to find the depletion date, updated live, as you type.

InputsLive
Mode
Savings balance
$
Annual return
%
Monthly withdrawal
$
Result
Savings duration
285 months
$500,000 @ 5.0% · $3000/mo withdrawals
Months lasting285
Years lasting23.8 yr
Balance$500,000
Monthly draw$3,000

CD rates vary by bank and term. FDIC insures up to $250,000 per depositor per bank. Early withdrawal penalties may apply.

Results are estimates. Consult a professional.

How it's calculated

How the savings distribution calculator works

A savings distribution calculator answers one critical retirement question: how long will my portfolio last if I withdraw a fixed amount every month? The answer depends on your starting balance, your monthly withdrawal amount, and the rate of return your portfolio earns while you draw it down.

The key insight is that your portfolio keeps earning interest even as you withdraw from it. If your monthly withdrawal is smaller than the interest earned that month, the portfolio never runs out — it is 'sustainable.' If withdrawals exceed interest earned, the balance shrinks each month and will eventually reach zero.

r = annual return / 12 (monthly rate)
n = log(W / (W P × r)) / log(1 + r)
Where: P = starting portfolio balance
W = monthly withdrawal amount
n = number of months the portfolio lasts
If W ≤ P × r, the portfolio is sustainable (lasts indefinitely)
Bengen (1994) — first systematic analysis of sustainable withdrawal rates
Example

Worked example: $500k at 5%, withdrawing $2,500/mo

Example: $500,000 balance · 5% annual return · $2,500/mo withdrawal

You retire with $500,000 invested at a 5% annual return. You plan to withdraw $2,500 every month. How long will the portfolio last?

r = 5% / 12 = 0.4167% per month
P × r = $500,000 × 0.004167 = $2,083.50 interest/month
W > P × r → portfolio is not sustainable
n = log(2,500 / (2,500 500,000 × 0.004167)) / log(1.004167)
= log(2,500 / 416.50) / log(1.004167)
= log(5.999) / 0.001858
≈ 422 months ≈ 35 years
35 years
A $500,000 portfolio earning 5% supports $2,500 monthly withdrawals for approximately 35 years — well past a typical 30-year retirement horizon.
Quick reference

Years a nest egg lasts by balance, return, and withdrawal

The table below shows how many years a portfolio lasts at three return rates and four withdrawal levels. 'Forever' means the withdrawal is less than monthly interest earned — the sustainable withdrawal scenario.

PortfolioReturn$2,000/mo$3,000/mo$4,000/mo$5,000/mo
$300,0004%19 yrs13 yrs10 yrs8 yrs
$500,0004%Forever29 yrs19 yrs15 yrs
$500,0005%Forever35 yrs23 yrs18 yrs
$750,0005%ForeverForever47 yrs27 yrs
$1,000,0006%ForeverForeverForeverForever

Source: calculated using Trinity Study methodology; assumes constant nominal return and monthly withdrawals.

Practical tips

Tips for making your savings last

Distribution planning is about balancing longevity risk (outliving your money) against lifestyle risk (under-spending and sacrificing quality of life). These habits help you strike the right balance.

  • Target a sustainable withdrawal rate — the classic '4% rule' (Bengen, 1994) suggests withdrawing no more than 4% of your starting balance per year. At 5% returns this is typically sustainable for 30+ years.
  • Adjust withdrawals in down years — reducing spending by 10–15% during a market downturn can dramatically extend portfolio life because it prevents selling assets at a loss.
  • Delay Social Security if possible — each year you delay past 62 (up to age 70) increases your benefit by 6–8%. A higher guaranteed income floor means you can withdraw less from your portfolio.
  • Hold a cash buffer — keeping 1–2 years of expenses in cash or a money market account lets you avoid selling investments during short downturns.
  • Re-run this calculator annually — market returns vary, and your withdrawal needs change. An annual recalculation keeps your plan grounded in current reality rather than outdated assumptions.
Accuracy & limits

Accuracy and limitations

This calculator assumes a constant annual rate of return every month. Real investment portfolios experience market volatility — years of strong returns and years of losses. Sequence-of-returns risk means that a portfolio can run out faster than the formula predicts if large losses occur early in retirement, even if the long-run average return is the same. Monte Carlo simulations and variable withdrawal strategies can address this limitation but are beyond the scope of this tool.

This calculator is provided for educational and planning purposes only. It does not constitute financial or retirement advice. Consult a licensed financial planner before making retirement distribution decisions.

Glossary

Savings distribution terms defined

The percentage of a portfolio balance withdrawn per year. The '4% rule' holds that a 4% initial withdrawal rate, adjusted for inflation, has historically sustained a 30-year retirement.
A monthly withdrawal amount that is less than or equal to the monthly interest earned on the portfolio. At this level, the principal is preserved indefinitely.
The danger that poor investment returns early in retirement permanently impair a portfolio, even if later returns are strong, because withdrawals lock in losses by selling depressed assets.
A 1998 academic paper by three Trinity University professors that analyzed historical U.S. market data to determine safe withdrawal rates for 15- to 30-year retirements.
A series of equal payments made at regular intervals. In this context, your monthly withdrawals are an annuity drawn from your portfolio.
The risk of outliving your savings. With life expectancies rising, financial planners commonly plan for 30-year retirements or longer.
About

About this savings distribution calculator

This calculator runs entirely in your browser — nothing you enter is sent to any server.

Browse more in our finance calculators, or explore the complete library on the free calculators page.

Questions

Frequently asked questions about the free savings distribution calculator

A savings distribution calculator is a free online tool that helps you calculate how many months a portfolio will last at a fixed monthly withdrawal. Annuity decline formula — months solved. It runs entirely in your browser with instant results and no sign-up.
No — actual loan terms depend on credit, income docs, and lender underwriting. Use this for planning and what-if scenarios; get a real Loan Estimate before making decisions.
When the calculator asks for them. PITI calculations include property tax, insurance, and PMI; raw P&I calculations don't.
Lenders round payment amounts and may include escrow buffers. Property tax and insurance change over time. Real payments vary 1-5% from these estimates.

Want a calculator built for your business?

Customize any of our 400+ tools to match your brand, or commission a new one tailored to how your business actually calculates — pricing, payroll, quotes, anything. Deployed on your domain, math runs in your visitors' browsers.