Compound interest calculator
What an investment with regular top-ups grows into: the final amount, your own contributions and what interest added.
Result
- Your own money paid in
- 1,300,000 ₽
- Added by interest
- 1,330,426 ₽
- Account balance
- Your own money paid in
Inputs
Year by year
| Year | Paid in, ₽ | Interest, ₽ | Balance, ₽ |
|---|---|---|---|
| 1 | 220,000 | 19,508 | 239,508 |
| 2 | 340,000 | 56,708 | 396,708 |
| 3 | 460,000 | 113,846 | 573,846 |
| 4 | 580,000 | 193,449 | 773,449 |
| 5 | 700,000 | 298,366 | 998,366 |
| 6 | 820,000 | 431,809 | 1,251,809 |
| 7 | 940,000 | 597,395 | 1,537,395 |
| 8 | 1,060,000 | 799,200 | 1,859,200 |
| 9 | 1,180,000 | 1,041,818 | 2,221,818 |
| 10 | 1,300,000 | 1,330,426 | 2,630,426 |
How it is calculated
Interest accrues every month on the balance and is added to it on the compounding date. A top-up made between two compounding dates earns simple interest until the nearest one.
The amount in today's prices is the result divided by accumulated inflation: that is how many of today's roubles it will replace. Tax is taken from the gain once, at the end of the term — the way a brokerage account is taxed; a bank deposit has a tax-free allowance, so for a deposit this is an upper estimate.
How to use it
- Enter the starting amount
What you invest up front. Zero is fine — then only the top-ups are counted.
- Set the rate and the term
Annual rate in percent, term in years and how often interest is compounded.
- Add top-ups, inflation and tax
The top-up amount and frequency and, if you wish, inflation and tax. The result, the growth chart and the year-by-year table update at once.
Questions
- What does compounding frequency mean?
- How many times a year interest is added to the balance and starts earning interest itself. At the same annual rate, monthly compounding beats annual, because the interest starts working earlier.
- When is the top-up made?
- As you choose: at the end of the period or at the start. At the start the result is slightly higher — every top-up works for one extra period. Top-ups do not have to follow the compounding frequency.
- Which rate should I enter?
- The one you consider achievable for your portfolio, not the highest you have seen. The calculator will honestly compute any rate you enter, and the output will be exactly as realistic as that rate is.
What this figure does not mean
This is arithmetic at a constant rate, not a forecast. The real return on an investment changes from year to year, and the sequence of good and bad years affects the outcome more than the average rate does. Inflation and tax are applied only if you set them, and are held constant too; fees are not included.