Retirement Calculator
What your retirement savings will be worth, and the income they can pay.
Good to know. Ten years of saving in your twenties can beat twenty in your forties. The early money compounds longest.
Not financial advice. Uses only the numbers and rates you enter — no live data.
How it works
In plain words
The return is turned into a real return by taking out inflation, so everything is in today’s money. Your savings and each month’s contribution grow at that rate until you retire. The income is the savings times the withdrawal rate, divided by 12.
The formula
Real return r = (1 + return) ÷ (1 + inflation) − 1 Savings = S × (1 + i)^m + c × ((1 + i)^m − 1) ÷ i, with i = monthly r Income = savings × withdrawal rate ÷ 12
Worked example
At 35 with 50,000 saved, putting away 500 a month at a 6% return and 2.5% inflation (a real return of 3.41%) grows to 490,528.52 in today’s money by 67. At a 4% withdrawal rate, that pays about 1,635 a month.
Sources
- Bengen, “Determining Withdrawal Rates Using Historical Data”, Journal of Financial Planning, 1994 The origin of the 4% rule.
- Cooley, Hubbard and Walz, “Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable”, AAII Journal, 1998 The “Trinity study” of withdrawal rates over 15 to 30 years.
- Brealey, Myers and Allen, Principles of Corporate Finance, chapter 2 The standard formulas for loan payments, compounding and present value, the same as a spreadsheet’s PMT and FV.
Sources checked September 29, 2026. 5 automated tests check its answers on every change.
About the retirement calculator
This calculator answers two questions: how much will I have when I retire, and what income will it pay? It works in today’s money, so the answer means something now. A pot of a million in 30 years sounds large, but after inflation it buys much less; the calculator shows what it would buy today.
Your savings and every monthly contribution grow at the investment return minus inflation. Contributions are taken to rise with prices, as pay usually does. Include any employer match in the monthly amount, as it is part of what goes in. The chart shows how much of the final pot is your own money and how much is growth, which takes over in the later years.
The income comes from the withdrawal rate. The well-known “4% rule” comes from US research on 30-year retirements: taking 4% of the starting pot in the first year, then raising it with inflation, survived almost every historical market. For a longer retirement or to be more careful, 3–3.5% is safer.
Returns are never guaranteed, and the order of good and bad years matters. The result is before tax on withdrawals and doesn’t include state pensions or Social Security, which come on top. Try a lower return to see a cautious case.
Questions people ask
How much do I need to retire?
A common guide is 25 times the yearly income you want from savings (the 4% rule), on top of any state pension or Social Security.
What return should I use?
Many planners use 5–7% a year before inflation for a mix of stocks and bonds, and less for cautious portfolios. Try a range.
Why show the result in today’s money?
Prices rise. Showing the pot in today’s money tells you what it will actually buy, which is what matters for planning.
What is the 4% rule?
A guideline that withdrawing 4% of your savings in the first year of retirement, then adjusting for inflation, has historically lasted at least 30 years.