Retirement Savings Calculator
This calculator projects what your retirement savings could grow to by the time you retire, based on what you have saved, what you add each month, and an assumed investment return. It splits the final balance into contributions and growth, and estimates the monthly income the balance might support.
It applies to any retirement account: a 401(k) or IRA in the US, a workplace pension or SIPP in the UK, superannuation in Australia, KiwiSaver in New Zealand, or an RRSP in Canada. Include your employer's match in the monthly contribution.
The compound growth formula
Future value = P(1 + r)n + M × [((1 + r)n − 1) ÷ r]
P is your current balance, M the monthly contribution, r the monthly return (annual ÷ 12) and n the months until retirement. The first term grows what you already have. The second grows your future contributions.
Time drives the result. At 6% a year, a dollar invested at 25 grows to about $10 by 65. A dollar invested at 45 grows to about $3.20. Same dollar, three times the outcome.
Worked example
A 30-year-old with $20,000 saved, contributing $500/month until 65 at a 6% average annual return:
| Projected balance at 65 | ≈ $875,000 |
|---|---|
| Total contributed | $230,000 |
| Investment growth | ≈ $645,000 |
| Sustainable income (4% rule) | ≈ $2,900 / month |
Almost three-quarters of the final balance is growth, not contributions. Starting ten years later (at 40 instead of 30) cuts the projected balance roughly in half. Delay is the most expensive choice in any retirement projection.
Choosing a realistic return and reading the result
Long-run stock market returns have averaged around 9–10% per year before inflation, and inflation takes 2–3% of that. Using 6–7% keeps the projection roughly in today's money, so the monthly income estimate reads at today's prices. Portfolios with bonds will sit lower. All-equity portfolios may run higher, with bigger swings.
The "4% rule" behind the income estimate comes from research on how much a retiree could withdraw each year (inflation-adjusted) without exhausting a balanced portfolio over 30 years. It is a planning benchmark, not a promise, but it turns a nest-egg number into a monthly income you can compare against your current spending.
Frequently asked questions
How much should I have saved for retirement by age?
A widely used benchmark: about 1× your salary saved by 30, 3× by 40, 6× by 50, 8× by 60 and 10× by 67. These are rough waypoints, not rules. Start where you are and let the calculator show what your current path produces.
What rate of return should I assume?
6–7% is a common long-run assumption for a diversified, stock-heavy portfolio after inflation. A conservative number makes pleasant surprises more likely than nasty ones.
Does the calculator include employer matching?
Only if you add it to the monthly contribution. If you contribute $400 and your employer adds $200, enter $600. The match is typically an instant 50–100% return, and the strongest reason to contribute enough to capture all of it.
Is the result adjusted for inflation?
The calculator projects in nominal terms using the return you enter. Enter a return net of inflation (for example 6% instead of 9%) and the result reads roughly in today's purchasing power.
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Last updated . Formulas are shown on the page and checked against the worked example.
This projection is for education only and is not financial advice. Investment returns are not guaranteed, and past performance does not predict future results. Consider speaking with a licensed financial adviser about your own situation.