Compound Interest Calculator
Runs locally in your browser. Nothing leaves your device.Calculate final balance, contributions and interest from a starting amount, annual rate, term and optional recurring deposits, fully local in your browser.
Calculate investment growth and optional recurring deposits entirely in your browser.
Projected final balance
$16,288.95
- Contributed
- $10,000.00
- Interest
- $6,288.95
Show growth
| Year | Balance | Contributed | Interest |
|---|---|---|---|
| 0 | $10,000.00 | $10,000.00 | $0.00 |
| 1 | $10,500.00 | $10,000.00 | $500.00 |
| 2 | $11,025.00 | $10,000.00 | $1,025.00 |
| 3 | $11,576.25 | $10,000.00 | $1,576.25 |
| 4 | $12,155.06 | $10,000.00 | $2,155.06 |
| 5 | $12,762.82 | $10,000.00 | $2,762.82 |
| 6 | $13,400.96 | $10,000.00 | $3,400.96 |
| 7 | $14,071.00 | $10,000.00 | $4,071.00 |
| 8 | $14,774.55 | $10,000.00 | $4,774.55 |
| 9 | $15,513.28 | $10,000.00 | $5,513.28 |
| 10 | $16,288.95 | $10,000.00 | $6,288.95 |
This calculation is an estimate. Actual results may differ because of fees, taxes, changing rates, rounding rules and product terms.
How it works
- 1
Enter starting amount and rate
Enter the starting amount, annual rate, term, and the desired compounding period.
- 2
Add contributions and inflation
Optionally add a regular contribution with its timing and an inflation rate for the purchasing-power calculation.
- 3
Review the ending balance and interest earned
Review the ending balance, total contributions, interest earned, and optionally the value in today's purchasing power.
Good to know
The compound interest calculator works out the ending balance from a starting amount, interest rate, term, and optional regular contributions - with control over details many simple calculators skip: nominal or effective annual rate, a selectable compounding frequency (daily to annual), contributions at the beginning or end of each period, and converting the ending balance into today's purchasing power.
Calculation runs locally in the browser. Constant returns are a model assumption; real investments fluctuate, and taxes on investment income are not deducted automatically.
Typical use cases
Compare nominal and effective rate
Choose between nominal and effective annual rate and adjust the compounding frequency to correctly compare offers from different banks or investment products.
Simulate a savings plan with regular contributions
Add a monthly, quarterly, or annual contribution and set whether it happens at the beginning or end of the period - this can make a noticeable difference over long terms.
Estimate the purchasing power of the ending balance
Add an expected inflation rate to see what the calculated ending balance would be worth in today's purchasing power - more realistic than looking at the nominal ending amount alone.
Tips for better results
Match the compounding period to the offer you’re comparing
Banks and brokers sometimes compound interest daily, monthly, or annually. Set the same compounding period as the offer, otherwise the results are not directly comparable.
Treat a constant return as a simplification
Real capital markets fluctuate from year to year. Use the result as a rough guide and also test a more conservative rate assumption instead of relying on a single optimistic figure.
Features
Selectable rate type and compounding period
Set a nominal or effective annual rate and a compounding period from daily to annual.
Contribution timing taken into account
Regular contributions can be made at the start or end of each period - the difference is calculated correctly.
Result in today's purchasing power
Add an inflation rate to also show the ending balance in today's purchasing power.
Frequently asked questions
What's the difference between nominal and effective rate?
The nominal rate is the stated annual rate without the compounding effect within the year. The effective rate accounts for the chosen compounding period and is correspondingly higher when compounding happens more than once a year.
Does contribution timing make a difference?
Yes. A contribution made at the start of a period earns interest for one period longer than one made at the end - over many years and contributions, this difference adds up noticeably.
Are taxes on interest income taken into account?
No, the calculator shows gross figures. Capital gains tax, allowances, and withholding tax vary by country and should be factored in separately.
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