Project how lump sums and monthly investments grow with compounding. Free, no signup, runs in your browser.
Estimates only — not financial, tax, or medical advice. Read disclaimer.
What is this tool?
This compound interest calculator projects how a starting amount and regular contributions grow. Contributions can be weekly to yearly, added at the start or end of each period, with an optional yearly increase. Compounding can be daily to yearly or continuous, years can include part years such as 2.5, and amounts show in your chosen currency. Under Tax, inflation and goal you can tax interest, see the value in today's money, and find the contribution needed to reach a target or how long your plan takes. A stacked bar chart and a yearly or monthly schedule show the growth, and the schedule downloads as CSV.
How to Use
- Enter a Starting amount and a Regular contribution, and choose how often you add it.
- Set the Annual interest rate, Years and Compounding.
- Optionally open Tax, inflation and goal to add tax, inflation or a target amount.
- Read the future value and breakdown, and hover or tap the chart to see any year.
- Switch the schedule between Yearly and Monthly, download it as CSV, or copy a share link.
Frequently Asked Questions
Is the return guaranteed?
No. The rate is an assumption for planning only.
What does adding contributions at the period start change?
Each contribution then earns interest for the period it is paid in, so the final value is a little higher. Period end matches most savings-plan formulas.
What is the effective annual yield (APY)?
It is the yearly return after compounding: (1 + rate / n)^n - 1. For example, 10% compounded monthly is 10.47% a year. With tax on interest, the after-tax yield is shown as well.
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