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Retirement Calculator

Project what your savings and monthly contributions grow to by retirement, how long that money pays the income you want, and how much you would need to save each month to close any gap.

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Save this calculation and come back to it any time. Members only — $5 every 3 months, ad-free.

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How to use the retirement calculator

  1. Enter your current age, the age you plan to retire, and a life expectancy to plan for. Planning to 90 or 95 is safer than using an average.
  2. Enter what you have saved for retirement so far and what you add each month.
  3. Enter the yearly return before retirement and the more cautious return after retirement.
  4. Enter the inflation rate you expect.
  5. Enter the monthly income you want in retirement and any other income such as Social Security or a pension, both in today's money.
  6. Read your savings at retirement, the amount you need, and how long the money lasts.

How the calculator works

Savings at retirement FV = S × (1 + r)^n + C × ((1 + r)^n − 1) ÷ i Monthly rate i = (1 + r)^(1/12) − 1 Withdrawal, year k W = (income − other income) × 12 × (1 + f)^(n + k) Amount needed Need = Σ W ÷ (1 + r₂)^k for k = 0 … m − 1 S = current savings, C = monthly contribution, r = return before retirement, r₂ = return after retirement, f = inflation, n = years to retirement, m = years in retirement

Contributions go in at the end of every month at the monthly rate that matches your yearly return, so a full year earns exactly r. In retirement, each year's withdrawal covers the gap between the income you want and your other income. The gap rises with inflation every year, comes out at the start of the year, and the rest keeps earning the after-retirement return. "Amount needed" is what you must have on your retirement day for the money to last exactly to your life expectancy.

Worked example

The defaults are a 35-year-old with $50,000 saved who adds $500 a month, earns 7% before and 5% after retiring at 67, expects 3% inflation, wants $5,000 a month and expects $2,000 from Social Security, planning to age 90.

  • Years to retirement: n = 67 − 35 = 32, and 1.07^32 = 8.715271
  • Current savings grow to $50,000 × 8.715271 = $435,764
  • Monthly rate: 1.07^(1/12) − 1 = 0.5654%, so the $500 contributions grow to $500 × 7.715271 ÷ 0.005654 = $682,267
  • Savings at 67: $435,764 + $682,267 = $1,118,030 (about $434,173 in today's money)
  • The gap is $3,000 a month, or $36,000 a year today. After 32 years of 3% inflation the first retirement withdrawal is $36,000 × 2.575083 = $92,703
  • Funding 23 years of withdrawals that rise 3% a year while earning 5% takes $1,739,709
  • The shortfall is $621,679 and the savings run out at age 80

To retire at 67 on this plan you would need to save about $956 a month instead of $500. Raising the contribution to $1,500 a month gives $2,482,564 at 67, enough to last past age 100.

Reading the result

  • Savings at retirement is in future dollars. The "today's money" figure removes inflation so you can compare it with prices now.
  • Shortfall or surplus compares that pot with the amount needed to fund your income to your life expectancy.
  • Monthly saving needed is the total monthly contribution that would close the gap, keeping your current savings and returns the same.

Three levers make the biggest difference: saving more, retiring a year or two later (fewer withdrawals and more growth), and spending a little less in retirement. Try each one and watch the shortfall change.

Assumptions and limits

Returns are smooth averages; real markets rise and fall, and a bad run early in retirement hurts more than the average suggests. Taxes, fees and changes in spending with age are not modelled, so enter returns after fees and income after tax. Use the Social Security calculator to estimate your benefit and the 401(k) calculator to include an employer match.

Frequently asked questions

How much do I need to retire?

It depends on the income you want, your other income and how long retirement lasts. A common shortcut is 25 times the yearly amount your savings must cover, which assumes a 4% first-year withdrawal. This calculator works it out year by year with your own inflation and return instead of a rule of thumb.

What return should I use?

Many planners assume 5% to 7% a year before inflation for a diversified, mostly stock portfolio held for decades, but no return is guaranteed. A lower return after retirement is common because retirees usually hold more bonds. Running the calculator at a few different rates shows how sensitive your plan is.

Should I include Social Security?

Yes, if you expect to receive it. Enter your estimated monthly benefit in today's dollars from your Social Security statement at ssa.gov. The calculator raises it with inflation, which matches how yearly cost-of-living adjustments work.

Why does the money run out before my life expectancy?

Your savings at retirement are smaller than the amount needed to fund the income gap for every year of retirement. Raise the monthly contribution, retire later, lower the income target, or check whether your expected return is realistic.

Related calculators

  • 401(k) Calculator — Project your 401(k) balance with your employer match, salary raises and the 2026 IRS contribution limits.
  • Social Security Calculator — Your monthly Social Security benefit at every claiming age from 62 to 70, with full retirement age and break-even ages.
  • Roth IRA Calculator — Project your tax-free Roth IRA balance with the 2026 contribution limits and compare it with a taxable account.
  • Compound Interest Calculator — How a starting balance and monthly contributions grow, with any compounding frequency.

Results are estimates for educational purposes and are not financial, tax or legal advice. See our disclaimer.