Finance & Loans

Compound Interest Calculator

Final balance and interest at yearly, monthly or daily compounding, with monthly contributions and a year-by-year table.

Updated: 28 October 2026

Result

Updates as you type

Balance after 10 years

16,470.09

Principal: 10,000.00
Total interest: 6,470.09
Effective annual rate (APY): 5.116%
Total return on money paid in: 64.7%

Gross figures: tax on interest and inflation are not included. The rate is assumed to stay the same for the whole period.

How it's calculated

With compound interest, each period's interest is added to the balance and the next period's interest is earned on the larger amount. The annual rate is divided by the number of compounding periods (12 for monthly), the per-period multiplier is (1 + rate / periods), and it is applied periods × years times. Monthly contributions are added at the end of each month and earn interest from the following period.

Balance = Principal × (1 + r / m)^(m × years) r: annual rate, m: periods per year

Effective annual = (1 + r / m)^m − 1

With contributions: balance + contribution at each month end; interest credited at period ends

Balance

= Principal × (1 + r / m)^(m × years) r: annual rate, m: periods per year

Effective annual

= (1 + r / m)^m − 1

With contributions: balance + contribution at each month end; interest credited at period ends

Worked example

10,000 principal, 5% a year, 10 years, monthly compounding:

Monthly multiplier: 1 + 0.05 / 12 = 1.0041667; periods: 12 × 10 = 120
Balance: 10,000 × 1.0041667^120 = 16,470.09; interest 6,470.09
Effective annual rate: 1.0041667^12 − 1 = 5.116%

Compound interest tables

Year by year

10,000 at 5% a year, monthly compounding: balance at the end of each year
Year	Interest that year	Year-end balance
Year: 1	Interest that year511.62	Year-end balance10,511.62
Year: 2	Interest that year537.79	Year-end balance11,049.41
Year: 3	Interest that year565.31	Year-end balance11,614.72
Year: 4	Interest that year594.23	Year-end balance12,208.95
Year: 5	Interest that year624.63	Year-end balance12,833.59
Year: 6	Interest that year656.59	Year-end balance13,490.18
Year: 7	Interest that year690.18	Year-end balance14,180.36
Year: 8	Interest that year725.49	Year-end balance14,905.85
Year: 9	Interest that year762.61	Year-end balance15,668.47
Year: 10	Interest that year801.63	Year-end balance16,470.09

Effect of the compounding frequency

10,000 over 10 years: balance by annual rate and compounding frequency
Annual rate	Yearly	Half-yearly	Quarterly	Monthly	Daily
Annual rate: 2%	Yearly12,189.94	Half-yearly12,201.90	Quarterly12,207.94	Monthly12,211.99	Daily12,213.96
Annual rate: 3%	Yearly13,439.16	Half-yearly13,468.55	Quarterly13,483.49	Monthly13,493.54	Daily13,498.42
Annual rate: 5%	Yearly16,288.95	Half-yearly16,386.16	Quarterly16,436.19	Monthly16,470.09	Daily16,486.65
Annual rate: 7%	Yearly19,671.51	Half-yearly19,897.89	Quarterly20,015.97	Monthly20,096.61	Daily20,136.18
Annual rate: 10%	Yearly25,937.42	Half-yearly26,532.98	Quarterly26,850.64	Monthly27,070.41	Daily27,179.10

Frequently asked questions

How is compound interest calculated?

Each period's interest is added to the balance, and the next period's interest is worked out on the larger balance: Total = Principal × (1 + rate / periods)^(periods × years). 10,000 at 5% a year for 10 years grows to 16,470.09 with monthly compounding and 16,288.95 with yearly compounding.

What is the difference between simple and compound interest?

Simple interest is paid only on the original principal; compound interest is also paid on the interest already earned. 10,000 at 5% for 10 years earns 5,000.00 in simple interest and 6,288.95 with yearly compounding.

Does it matter whether interest compounds monthly or yearly?

Yes. The more often interest is added at the same nominal rate, the higher the balance. 5% compounded monthly is an effective annual rate of 5.116%; daily compounding is slightly higher still. Banks call this the APY or AER.

How are monthly contributions handled?

Each contribution is added at the end of the month and earns interest from the next period on. If you pay in at the start of the month, your real balance will be a little higher.

Is tax on interest included?

No. The result is gross interest. If interest is taxed where you live, enter the after-tax rate to see the net balance.

Does the calculator account for inflation?

No. The balance is a nominal amount. To see the real return, compare the growth with inflation over the same years; a rate below inflation loses purchasing power.

A mathematical projection at a fixed gross rate; tax, inflation, fees and rate changes are not included. Results are for guidance only.

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