Compound interest calculator
| Year | Contributed | Growth | Balance |
|---|---|---|---|
| 1 | $16,000 | $919 | $16,919.19 |
| 2 | $22,000 | $2,339 | $24,338.58 |
| 3 | $28,000 | $4,294 | $32,294.31 |
| 4 | $34,000 | $6,825 | $40,825.16 |
| 5 | $40,000 | $9,973 | $49,972.70 |
| 6 | $46,000 | $13,782 | $59,781.53 |
| 7 | $52,000 | $18,299 | $70,299.43 |
| 8 | $58,000 | $23,578 | $81,577.68 |
| 9 | $64,000 | $29,671 | $93,671.22 |
| 10 | $70,000 | $36,639 | $106,639.02 |
| 11 | $76,000 | $44,544 | $120,544.25 |
| 12 | $82,000 | $53,455 | $135,454.70 |
| 13 | $88,000 | $63,443 | $151,443.02 |
| 14 | $94,000 | $74,587 | $168,587.14 |
| 15 | $100,000 | $86,971 | $186,970.62 |
| 16 | $106,000 | $100,683 | $206,683.03 |
| 17 | $112,000 | $115,820 | $227,820.45 |
| 18 | $118,000 | $132,486 | $250,485.91 |
| 19 | $124,000 | $150,790 | $274,789.85 |
| 20 | $130,000 | $170,851 | $300,850.72 |
Estimate for planning only, not a projection of any specific investment. It assumes a constant return every period with no fees or taxes, which real markets do not deliver. The return rate is your own input, not a promised or historical figure.
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Frequently asked questions
How is compound interest calculated?
Each period your balance earns a return, and that return is added to the balance so the next period earns on a larger amount. This calculator applies your annual rate daily, weekly, monthly, or once a year, adds your contribution on the schedule you choose (weekly, every two weeks, monthly, or every two months), and repeats for the number of years you set. Growth builds slowly at first and faster later because you are earning returns on your past returns.
Does compounding daily, weekly, monthly, or annually make a big difference?
Monthly compounding applies one twelfth of the annual rate twelve times a year, so interest starts earning on interest sooner and the ending balance is slightly higher than annual compounding at the same rate. Daily compounding splits the rate into 365 smaller steps for a little more still. The gap widens with higher rates and longer time frames, and it stays small at ordinary rates.
What return rate should I use?
That is your own assumption, not a number this tool supplies. A rate is only a planning input, and no real investment returns the same amount every year. Lower, more conservative rates give a more honest floor for planning; you can try a range of rates to see how sensitive the result is to that one assumption.
How much of the final balance is growth versus what I put in?
The tool splits the ending balance into total contributions (your starting balance plus every contribution) and compound growth (everything above that). Over long horizons the growth portion can exceed what you contributed, which is the whole point of compounding.