Annuity Calculator
Work out the future value of regular contributions, or the periodic income a lump sum can pay out, across monthly, quarterly, or annual periods.
Frequently Asked Questions
What is an annuity?
An annuity is a series of equal payments made at regular intervals. It can mean money you pay in to build a balance, or a steady income stream paid out from a lump sum.
Can it find my monthly payout?
Yes. Switch to payout mode, enter your principal, rate, and the number of years, and choose a monthly frequency to see the income each period.
Does it handle different frequencies?
Yes. Both modes support monthly, quarterly, and annual periods, and the rate is converted to match the frequency you pick.
Understanding the Annuity Calculator
An annuity is a stream of equal payments made at regular intervals, and this calculator covers both sides of one. In accumulation mode it shows the future value of regular contributions growing at a fixed rate, so you can see what consistent saving becomes over time. In payout mode it works backwards from a lump sum to reveal the steady income that principal can provide over a set number of years. Everything runs in your browser, adapts to your chosen currency, and supports monthly, quarterly, or annual periods, making it handy for retirement planning, pension estimates, and comparing structured savings or income options side by side.
How it works
Pick a mode with the toggle at the top. In accumulation mode you enter your contribution per period, the annual interest rate, the number of years, and how often you contribute; the tool compounds each deposit to the end date and reports the future value, total contributed, and growth earned. In payout mode you enter a principal, an annual rate, the payout length in years, and a frequency; it solves for the level payment that exactly drains the balance, then shows the periodic payout, total paid, and interest earned. The annual rate is divided by the number of periods per year, and the year count is multiplied by it, so frequencies stay consistent.
Worked example
Suppose you save 500 a month at 6% annual interest for 20 years. Here i = 0.06 / 12 = 0.005 and n = 240. The future value works out to about 231,020, of which 120,000 is your contributions and roughly 111,020 is growth. Now flip to payout: a 500,000 principal at 5% paying out monthly for 25 years gives i = 0.0041667 and n = 300, producing a payment near 2,923 each month, about 876,900 paid in total across the 25 years.
Tips & common mistakes
- Use accumulation mode while you are saving toward a goal, and payout mode once you want to turn a lump sum into income.
- Match the rate to the frequency mindset: enter the annual rate and let the tool convert it, rather than dividing it yourself.
- Returns are assumed constant; real markets vary, so test a lower rate to see a more conservative outcome.
- The estimate ignores taxes, fees, and inflation, which all reduce real spending power over long horizons.
- For a fixed lump sum, a longer payout period lowers each payment, while a shorter one raises it.
- Annuity products from insurers add charges and guarantees this simple math does not capture, so treat results as a baseline.
Sources & methodology
- • General time value of money formulas for ordinary annuities (future value and present value of an annuity)
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Reviewed by the TopOpenTools editorial team · Last updated June 2026. These tools provide general estimates for educational purposes only and are not financial, tax, insurance, investment, or medical advice. Verify important decisions with a qualified professional.