How to use Investment Calculator

The short answer

To project an investment, enter the starting amount, regular contribution, annual return and years. $10,000 plus $500 a month at 7% for 20 years grows to about $299,000; the table shows the balance each year.

It runs in your browser. What you enter is not uploaded.

How to use it

Enter your values in the fields; defaults show a worked example.

Pick the units or options that apply to you.

Read the result, which updates instantly as you type.

Check the formula note under the result to see exactly how it was worked out.

Limits worth knowing

Is the return compounded monthly? It compounds once per contribution period (monthly, quarterly or yearly) at the annual rate divided by the number of periods.

What return should I assume? Many planners use 5–7% after inflation for a diversified stock portfolio over long periods, but returns are never guaranteed.