Compound Interest Calculator
See how compound interest turns your savings into long-term wealth. Enter your principal, expected annual return, compounding frequency, time horizon, and optional monthly contribution — then export the year-by-year breakdown as CSV.
Year-by-year breakdown
| Period | Contributions | Interest | Balance |
|---|---|---|---|
| Year 1 | $13,000 | $839 | $13,839 |
| Year 2 | $16,000 | $1,956 | $17,956 |
| Year 3 | $19,000 | $3,370 | $22,370 |
| Year 4 | $22,000 | $5,103 | $27,103 |
| Year 5 | $25,000 | $7,179 | $32,179 |
| Year 6 | $28,000 | $9,621 | $37,621 |
| Year 7 | $31,000 | $12,457 | $43,457 |
| Year 8 | $34,000 | $15,715 | $49,715 |
| Year 9 | $37,000 | $19,425 | $56,425 |
| Year 10 | $40,000 | $23,620 | $63,620 |
| Year 11 | $43,000 | $28,336 | $71,336 |
| Year 12 | $46,000 | $33,609 | $79,609 |
| Year 13 | $49,000 | $39,480 | $88,480 |
| Year 14 | $52,000 | $45,992 | $97,992 |
| Year 15 | $55,000 | $53,192 | $108,192 |
| Year 16 | $58,000 | $61,130 | $119,130 |
| Year 17 | $61,000 | $69,858 | $130,858 |
| Year 18 | $64,000 | $79,434 | $143,434 |
| Year 19 | $67,000 | $89,919 | $156,919 |
| Year 20 | $70,000 | $101,379 | $171,379 |
How this compound interest calculator works
Compound interest is interest calculated on both the initial principal and the
accumulated interest from previous periods. The more frequently interest is
compounded, the faster your balance grows. This calculator applies the standard
compound interest formula A = P(1 + r/n)nt over your chosen
horizon, then layers in recurring contributions period by period so your projection
reflects regular saving — not just a one-time deposit.
Choosing a compounding frequency
Annual compounding is the most conservative option and is typical for basic certificate of deposit products. Monthly compounding matches most savings accounts and is the default here. Daily compounding produces slightly higher returns and is used by some high-yield accounts and credit unions.