Compound interest calculator

The compound interest calculator multiplies principal by (1 + rate/100) to the power of years. 10000 at 6% for 10 years ends near 17908.48, and interest is about 7908.48. Compounding is once a year, with no deposits along the way and no tax.

Final = principal × (1 + rate/100)^years. 10000, 6%, and 10 years land near 17908. A term with months and withholding is on term deposit. Article: compound interest.

Input data

Result

Principal, Annual rate (% p.a.) and Years. The result shows up here.

How results are calculated

Compound interest means earnings join the principal and earn in the next year. On this page compounding is once a year: final = principal × (1 + rate/100)^years. Total interest is final minus principal. There are no extra deposits, fees, or Belka tax, the Polish capital-gains withholding.

At 10000, 6%, and 10 years the result is about 17908.48 at the end and 7908.48 of interest. 25000 at 5% for 5 years ends near 31907.04. A smaller 5000 at 8% for 15 years grows to about 15860.85, because the longer horizon multiplies harder.

Type Principal, Annual rate (% p.a.), and Years. The 10000, 6, and 10 placeholders are the first example. Click Calculate and read the final amount, interest, the multiplier, and the year-by-year table. Blank years do not insert a decade.

The term deposit page uses simple interest from months and can take off 19%. Savings interest is also simple, but in years and with no tax. Future value (FV) adds contributions, other compounding, and optional inflation. This calculator stays with three fields.

A flat rate for a decade is a classroom assumption. A promo that drops after a year, and tax on interest, will move a real balance. Compare with the deposit page before you call 17908 a plan.

Type 10000, 6, and 10. Check about 17908. Then try 5 years at 25000 and 5% to see about 31907.

How to use the calculator

  1. In Principal, type the start, for example 10000.
  2. In Annual rate (% p.a.), type the percent, for example 6. In Years, type the horizon, for example 10.
  3. Click Calculate. At 10000, 6, and 10 the final should be about 17908.48, and interest about 7908.48.
  4. Scan the year-by-year table. Each row applies the same 6% to the new base.
  5. If you want months and 19% on simple interest, open term deposit. Contributions live on future value.

Yearly compounding with no deposits

Final = principal × (1 + rate/100)^years. 10000 at 6% for 10 years ends near 17908.48, and interest is about 7908.48.

compound
Once-a-year compounding in this calculator. 10000 × 1.06^10 ≈ 17908.48. No deposits along the way and no tax.
Principal
The starting field. 25000 at 5% for 5 years is about 31907. 5000 at 8% for 15 years is about 15861.
interest
Final minus principal. About 7908.48 from 10000 at 6% for 10 years. Not a deposit with 19% withholding.

Usage examples

Example 1

  • Principal: 10,000
  • Rate: 6%
  • Years: 10

Final ≈ 17,908.48
Interest ≈ 7,908.48

A decade of compounding nearly doubles the capital at 6%.

Example 2

  • Principal: 25,000
  • Rate: 5%
  • Years: 5

Final ≈ 31,907.04

A shorter horizon yields less compounding effect despite a larger principal.

Example 3

  • Principal: 5,000
  • Rate: 8%
  • Years: 15

Final ≈ 15,860.85

A long horizon and higher rate strongly multiply a smaller principal.

Example 9

  • 25,000
  • 5%
  • 8 years

Final 36,936.39

What does 25,000 become at 5% compounded for 8 years? Final 36,936.39.

Example 10

  • 5,000
  • 8%
  • 15 years

Final 15,860.85

What does 5,000 become at 8% compounded for 15 years? Final 15,860.85.

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FAQ

What does 10000 at 6% for 10 years become?

Final about 17908.48, interest about 7908.48. That is 10000 × 1.06^10.

What about 25000 at 5% for 5 years?

Final about 31907.04. A shorter span compounds less even with a larger principal.

What about 5000 at 8% for 15 years?

Final about 15860.85. A longer horizon and a higher rate multiply a smaller start hard.

Does withholding come off the 7908?

No. This calculator does not ask for tax. Take 19% of a ready gain on capital-gains tax or on the deposit page.

How is this different from a term deposit?

The deposit page has months and optional 19%, with no compounding. Here you have years and yearly compounding, with no withholding.

Can I add 200 every month?

Not on this page. Regular contributions live on the future value calculator.

How often does the calculator compound?

Once a year. There is no monthly or quarterly list. A custom period count lives on FV.

How is savings interest different?

There, gain = principal × rate × years, with no compounding. At 10000, 5%, and 3 years you get exactly 1500, not 1.05^3.

Does 6% for 10 years always nearly double?

In this formula 1.06^10 ≈ 1.79, so 10000 goes to 17908, not 20000. Another rate gives another multiplier.

Do blank years mean 10?

No. You must type the horizon. The 10 placeholder is a hint.

Knowledge sources

Compound interest in this calculator is the formula from the rate and years you type.

Page updated in 2026.