Compound Interest Calculator

Enter a starting amount, an annual interest rate, and a number of years to see what compound interest does to a balance over time. Add a regular contribution and pick how often interest compounds - daily, monthly, quarterly, or yearly - to model a savings account, a retirement fund, or any investment that reinvests its returns. A year-by-year table breaks down how much you put in versus how much the interest earned, and it all runs in your browser.

Math

Starting amountAnnual interest rate %YearsCompoundingContribution per periodContribution timing

Final balance

47,526.55

Total interest

13,526.55

Total contributed

34,000.00

Years

Growth by year

Year	Contributed	Interest	Balance
1	2,400.00	567.39	12,967.39
2	2,400.00	719.21	16,086.60
3	2,400.00	878.79	19,365.39
4	2,400.00	1,046.54	22,811.93
5	2,400.00	1,222.87	26,434.80
6	2,400.00	1,408.23	30,243.03
7	2,400.00	1,603.06	34,246.09
8	2,400.00	1,807.87	38,453.96
9	2,400.00	2,023.15	42,877.11
10	2,400.00	2,249.45	47,526.55

What this tool does

Type in your starting balance, the annual rate, and how long you'll leave the money invested. Set a contribution to add a fixed amount every compounding period, and choose how often interest compounds. The calculator returns the final balance, the total interest earned, and the total you paid in, plus a year-by-year breakdown. Change any input and the numbers update right away.

How compounding works

Compound interest earns interest on your interest. Each period the balance grows by the periodic rate, then that larger balance earns even more the next period. The more often it compounds - daily beats monthly beats yearly at the same annual rate - the faster it grows. Regular contributions stack on top, and money added at the start of a period earns slightly more than money added at the end.

Reading the growth table

The table rolls the schedule up by year. The contributed column is what you paid in that year, the interest column is what the balance earned, and the balance column is where you stand at the end of each year. Watching the interest column climb past the contributed column is the clearest way to see compounding take over from your own deposits.