Future Value of Annuity Calculator

What Is the Future Value of an Annuity?

An annuity is a series of equal payments made at regular intervals. The future value of an annuity tells you what all those payments will be worth at a future date, accounting for compound interest on each payment.

Ordinary Annuity vs Annuity Due

An ordinary annuity pays at the end of each period. An annuity due pays at the beginning. Annuity due is slightly more valuable because each payment earns one extra period of interest.

Why Does This Matter for Retirement Planning?

Many people find it genuinely surprising how much regular contributions can grow over time. Even modest monthly payments, held over decades, can accumulate into a significant sum. That is the power of compounding at work. It can help to think of each payment not just as a saving, but as a seed earning its own interest. The earlier those payments start, the longer each one has to grow. This is worth noting when thinking about pension contributions or long-term savings habits.

Patterns commonly observed

One thing people often overlook is the difference between nominal and real returns. An interest rate looks more impressive before inflation is factored. Another common oversight is assuming the rate stays constant throughout. In practice, rates fluctuate. These figures are best treated as illustrations rather than predictions. One approach is to run the calculator with a few different rate assumptions to get a broader sense of the range of possible outcomes.

A worked example

Try the defaults: regular payment amount of 500, annual interest rate of 6, number of years of 20. The tool returns 18,392.80. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Regular Payment Amount, Annual Interest Rate, and Number of Years. The rate and the time horizon usually dominate — compounding means a small change in either reshapes the final figure more than a similar shift in contribution size. Test this by doubling one input at a time.

The formula behind this

This calculator applies the future value of annuity formula, which compounds regular periodic payments at a constant interest rate over a specified time period. The calculation assumes fixed payment amounts, consistent interest rates, and no additional fees or withdrawals. Results are illustrative estimates based on these assumptions. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

Turning the result into a plan

A projection is just a starting point. The real work is setting the monthly amount aside automatically so the saving happens before you can spend it. Most people who hit savings goals set up a standing order on payday; most who miss them rely on willpower at month-end.

What this doesn't capture

The calculation assumes a steady savings rate and a stable interest rate. Real saving journeys include emergencies, windfalls, and rate changes — especially in easy-access products. The figure is a direction of travel, not a guarantee.