Retirement and income · Time value of money
Annuity calculator.
Pick one of three questions: what regular deposits grow to, what a stream of payments is worth today, or what level payment a lump sum can fund for a set number of years.
A level payment stream is worth payment × [1 − (1 + i)−n] ÷ i today and payment × [(1 + i)n − 1] ÷ i at the end, where i is the rate per period and n the number of payments. An annuity due pays at the start of each period and is worth (1 + i) times more.
Your annuity
Your estimate
How the annuity maths works
With rate i per period (the annual rate divided by payments per year) and n payments, a level payment of 1 is worth [(1 + i)n − 1] ÷ i at the end of the term and [1 − (1 + i)−n] ÷ i today. If payments fall at the start of each period (an annuity due), multiply either factor by (1 + i). With a 0% rate the factors are simply n. A starting balance grows by (1 + i)n.
Worked example
Deposit $500 a month at 6% a year (0.5% a month) for 10 years on top of $10,000 already saved. The balance grows to $18,193.97 and the deposits to $81,939.67, so the total is $100,133.64 from $70,000 of your own money. For payouts, $100,000 at 5% paid monthly over 20 years supports $659.96 a month. The form is preloaded with the first example.
What this page does not do
- It does not price a product. An annuity from an insurer is a contract, and its payout also reflects mortality, fees, guarantees and the insurer’s own pricing. Use this page to test what a quote implies, not to predict one.
- It assumes a constant rate and no tax, fees or inflation. Payments compound at the payment frequency.
- Contribute and payout modes stop at the end of the term; they do not show what happens after.
Reference: U.S. SEC Investor.gov, Annuities, read October 4, 2026, describes an annuity as a contract with an insurance company that pays periodic income. The formulas above are textbook mathematics and have no yearly rates to go stale.
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 start, so each payment earns one extra period of interest and the total is (1 + i) times larger.
Can I use this for a lottery or structured settlement buyout?
You can test a discount rate: choose present value, enter the payment, term and the rate a buyer offers, and compare the result with the cash offer. The page does not judge whether an offer is fair.
Why is my insurance quote lower than the payout shown here?
Insurers price in life expectancy, costs and guarantees, and a quote may include inflation protection or survivor benefits. This page is a plain interest calculation.
Is the interest rate compounded?
Yes, at the payment frequency you choose. A 6% annual rate paid monthly uses 0.5% per month.
Estimate only
This page is educational and is not financial or tax advice. Real annuity contracts differ in fees, guarantees and taxation; read the contract and ask a licensed adviser. Calculations run in your browser; nothing is sent anywhere.