An annuity is simply a series of equal payments at regular intervals. When you save on a schedule — monthly IRA contributions, a yearly deposit into a college fund, a company setting aside money to replace a machine — the question is what those payments will add up to by the end. This calculator answers it for both payment timings and for payments that grow over time.
How to use the future value of annuity calculator
- Enter the payment amount and the payment frequency.
- Enter the number of years the payments continue.
- Enter the annual interest rate and the compounding frequency (“same as payments” is the textbook default).
- Choose ordinary (payments at the end of each period) or annuity due (payments at the start).
- Optionally enter a payment growth rate per period to model rising contributions.
The results compare both timings, and the chart and table show cumulative payments and interest year by year.
Annuity future value formulas
For an ordinary annuity of n payments of P at rate r per period:
For an annuity due, multiply by (1 + r). For payments growing at g per period:
The bracketed term in the first formula is the future value annuity factor, the same number printed in a future value of annuity table.
Worked example
You deposit $300 at the end of every month for 20 years at 5% compounded monthly.
- Rate per month: 5% ÷ 12 = 0.416667%; n = 240
- Annuity factor: (1.00416667240 − 1) ÷ 0.00416667 = 411.033669
- Future value: $300 × 411.033669 = $123,310.10
- You paid in $72,000; interest supplied $51,310.10
As an annuity due, the same deposits grow to $123,823.89, about $514 more. If instead you raise the deposit by 0.25% every month (roughly 3% a year), the final deposit is $544.86 and the ordinary annuity reaches $160,539.35.
Quick reference: $100 a month
Future value of $100 deposited at the end of each month, compounded monthly:
| Years | 3% | 5% | 7% |
|---|---|---|---|
| 10 | $13,974.14 | $15,528.23 | $17,308.48 |
| 20 | $32,830.20 | $41,103.37 | $52,092.67 |
| 30 | $58,273.69 | $83,225.86 | $121,997.10 |
Scale the row to your own payment: $250 a month for 20 years at 5% is 2.5 × $41,103.37 = $102,758.43.
Growing annuities in practice
Contributions rarely stay flat. A worker who saves $5,000 at the end of each year and increases it 3% annually for 30 years, earning 6%, accumulates $552,704.78 — over $157,000 more than flat $5,000 deposits would produce. Use yearly frequency for this kind of model so the growth rate reads as a yearly raise.
Related calculations
To find the deposit needed for a target instead, use the savings goal calculator. To value a stream of payments you will receive rather than make, see the present value of annuity calculator. And for a lump sum plus payments in one calculation, the general future value calculator combines both.
Results assume a constant interest rate and on-time payments. They are estimates for planning and study, not financial advice.
Frequently asked questions
What is the future value of an annuity?
It is the total that a series of equal payments will be worth at the end of the last period, including all the interest earned along the way. Regular retirement contributions and sinking-fund deposits are common examples.
What is the difference between an ordinary annuity and an annuity due?
In an ordinary annuity, payments are made at the end of each period; in an annuity due, at the beginning. Because every payment in an annuity due earns one extra period of interest, its future value equals the ordinary value times (1 + r).
What is a growing annuity?
An annuity whose payment rises by a fixed percentage each period — for example, yearly retirement contributions that increase with your salary. Its future value is P × [(1 + r)^n − (1 + g)^n] ÷ (r − g).
How much will $300 a month grow to in 20 years?
At 5% compounded monthly, deposited at the end of each month, it grows to $123,310.10: $72,000 of payments plus $51,310.10 of interest. Making the deposits at the start of each month raises that to $123,823.89.
What is a sinking fund?
Money set aside in regular installments to pay for a known future cost, such as replacing equipment or retiring a bond. The required installment is the target divided by the future value annuity factor.