Retirement Calculator
Will your savings last? See the gap in today’s money and what would close it.
How to use Retirement Calculator
- Enter your age, when you want to retire and the age you want the money to last to.
- Enter what you have saved, what you add each month, what you expect to spend per year and any pension or Social Security income.
- Read whether the plan holds, the surplus or shortfall, and the monthly saving that would fund it.
How it works
Everything is shown in today’s money, so the numbers mean what they would mean in a shop today. To do that, each return is converted to a real (after-inflation) return: real = (1 + return) ÷ (1 + inflation) − 1. With a 6% return and 2.5% inflation the real return is about 3.41%.
Before retirement your savings grow monthly at the real return, with your monthly deposit added at the end of each month. From retirement, the amount you need from savings (spending minus pension or Social Security income) is taken out at the start of each month while the rest keeps earning the retirement return. The amount needed is the pot that pays that income exactly until your plan age.
The result also shows the level monthly saving that would exactly fund the plan, and the yearly spending your projected savings can support.
Example
Age 35, retiring at 65, planning to 85, with 40,000 saved, 1,000 a month added and spending of 20,000 a year. If returns only match inflation (0% real), you reach 40,000 + 360 × 1,000 = 400,000 at 65, which pays 20,000 a year for exactly 20 years.
Frequently asked questions
How much do I need to retire?
Enough to cover the gap between what you will spend and your guaranteed income (pension, Social Security), for as long as you live. This calculator works that out for your numbers instead of using a rule of thumb such as 25 times yearly spending.
Why are results in today’s money?
A million in 30 years buys much less than a million today. Showing everything at today’s prices lets you compare the result with your current spending. The balance in future money is also shown for reference.
What return should I assume?
No one knows future returns. Many planners use 4–7% a year before inflation for a mix of shares and bonds, and less in retirement when investments are usually safer. Try a cautious and an optimistic case.
Does it include Social Security or a pension?
Yes. Enter the yearly amount you expect, in today’s money, under "Pension or Social Security". It reduces what must come from savings.
Does it account for tax?
No. Enter spending and income after tax, or add your expected tax to the spending figure.
Limitations
- Returns and inflation are constant; real markets rise and fall, and a bad early decade matters more than the average.
- Taxes, fees, healthcare shocks and changes in pension rules are not modelled.
- Other income is assumed to start at retirement and keep up with inflation.
- For information only. It is not financial advice and not an offer of credit.
Last reviewed November 9, 2026. How we build and test tools.