Savings Account Interest Calculator
Savings account interest depends on the rate and how often it compounds. Monthly compounding earns a little more than annual compounding at the same headline rate, and regular deposits add to the balance faster than the interest alone.
Balance after growth
$10,407.42
- Interest earned
- $407.42
- Effective annual rate
- 407.42%
Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.
The formula this calculator uses
Balance = principal x (1 + rate/n)^(n x t)
- principal
- Starting balance
- rate
- Annual nominal interest rate
- n
- Compounding periods per year
- t
- Years, or months for the monthly figure
How to check the result by hand
- 1
Identify the nominal rate
Use the annual rate quoted, not the effective rate, and confirm how often the account compounds.
- 2
Convert to the period rate
Divide the annual rate by the number of compounding periods. For monthly compounding, divide by twelve.
- 3
Raise the compounding factor
One plus the period rate, raised to the total number of periods, gives the growth factor.
- 4
Multiply by the principal
The starting balance times the growth factor gives the balance at the end of the period.
- 5
Add regular deposits
If you contribute each month, compute the future value of the deposit stream separately and add it to the grown principal.
For worked examples, common mistakes and the limits of this formula, read the full How To Calculate Savings Account Interest page.