Number One Investment Calculator

See how savings can grow.

Enter a starting amount, a monthly contribution, and an expected annual return. We compound monthly, add savings at the end of each month, and show the first year month by month, then a summary for each year after that.

Compound interest earns returns on both the original principal and the accumulated interest, producing exponential growth over time. Even small amounts can become substantial when left to compound for many years, which is why starting early is often more powerful than investing large sums later.

This is the power of compound interest!

Pro tip! Time in the market does a lot of the work. Nudge the monthly amount to see how regular savings change the final balance.