Annuity Calculator

Enter a level payment, an annual rate, a term and how often you pay to find the future value, present value, total contributions and interest earned. Switch between an ordinary annuity (paid at period end) and an annuity due (paid at the start).

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Enter the payment details and press Calculate annuity.

The annuity formulas

An annuity is a series of equal payments made at regular intervals. With a periodic rate i (annual rate ÷ payments per year) and n total payments, the two key figures for an ordinary annuity are:

FV = PMT × ( (1+i)n − 1 ) ÷ i PV = PMT × ( 1 − (1+i)−n ) ÷ i

Here FV is the future value (what the payments grow to by the end), PV is the present value (the lump sum the stream is worth today), and PMT is each payment. For an annuity due, every payment arrives one period earlier, so both FV and PV are multiplied by (1 + i). When the rate is zero, FV and PV both collapse to PMT × n.

Worked example

A $500 payment every month for 10 years at 6% a year (ordinary annuity):

Periodic rate: 6% ÷ 12 = 0.5% (i = 0.005).
Number of payments: 10 × 12 = 120.
Future value: 500 × ((1.005)120 − 1) ÷ 0.005 = $81,939.67.
Present value: 500 × (1 − 1.005−120) ÷ 0.005 = $45,036.73.
Contributions vs interest: you pay in 120 × $500 = $60,000, so the interest earned is $81,939.67 − $60,000 = $21,939.67.

Ordinary annuity vs annuity due

The only difference is when each payment lands. An ordinary annuity (mortgages, bonds, most loans) pays at the end of each period. An annuity due (rent, leases, many insurance premiums) pays at the start, giving every payment one extra period of growth.

TimingWhen paidFV of $500/mo, 6%, 10 yrPV
Ordinary annuityEnd of period$81,939.67$45,036.73
Annuity dueStart of period$82,349.37$45,261.91
Note: an annuity due is always worth more than an ordinary annuity with the same payments — by exactly the factor (1 + i) — because the money is invested for one additional period.

Frequently asked questions

What is the difference between an ordinary annuity and an annuity due?

An ordinary annuity pays at the end of each period; an annuity due pays at the beginning. Because each payment in an annuity due sits in the account one period longer, its future and present values are both higher by a factor of (1 + i).

How is the future value of an annuity calculated?

Future value uses FV = PMT × ((1 + i)n − 1) ÷ i, where PMT is the payment, i is the periodic rate and n is the number of payments. For an annuity due you multiply the result by (1 + i).

What is the present value of an annuity?

Present value is what the whole future stream of payments is worth today: PV = PMT × (1 − (1 + i)−n) ÷ i. It is the lump sum that, invested at rate i, would fund all the payments.

How much of the future value is interest?

Total contributions equal the payment times the number of payments (PMT × n). Interest earned is the future value minus those contributions — the growth your money produced on top of what you put in.

MB
Mustafa Bilgic · Editor, Calcool
The annuity future- and present-value formulas are standard time-value-of-money mathematics. For background on compounding and discounting, see Investor.gov. Last updated 20 June 2026.

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