Interest Calculator
Find what savings grow to with compound interest, regular contributions at the beginning or end, tax and inflation.
Change the values and press Calculate to work out your own figures.
Enter the starting amount, contributions, rate and length.
| Year | Contributions | Interest | Balance |
|---|---|---|---|
| 1 | $5,000.00 | $1,250.00 | $26,250.00 |
| 2 | $5,000.00 | $1,562.50 | $32,812.50 |
| 3 | $5,000.00 | $1,890.63 | $39,703.13 |
| 4 | $5,000.00 | $2,235.16 | $46,938.28 |
| 5 | $5,000.00 | $2,596.91 | $54,535.20 |
Show the working
- each month: balance × periodic rate × (1 − tax) is added, with contributions at the start or end
- periodic rate = (1 + r ÷ n)^(n ÷ 12) − 1
How to use it
Enter the starting amount, contributions, rate and length.
Enter amounts without commas or with them; rates are percentages (5 for 5%). Negative amounts are allowed where a sign means money paid out.
Key facts
each month: balance × periodic rate × (1 − tax) is added; contributions at the start or end periodic rate = (1 + r ÷ n)^(n ÷ 12) − 1
Questions
What does $20,000 grow to at 4% compounded daily for 5 years?
$24,427.79.
What is $20,000 plus $5,000 a year at 5% for 5 years?
$54,535.20 with contributions at the start of each year.
Formulas
each month: balance × periodic rate × (1 − tax) is added; contributions at the start or end periodic rate = (1 + r ÷ n)^(n ÷ 12) − 1
Sources
Limitations
- Results are estimates for planning, not offers or financial advice; lenders and banks may round, count days or time payments differently.
- Rates are nominal annual rates compounded as you choose; payments at a different frequency use the equivalent periodic rate.