Home › Savings & retirement · Updated 2026-10-15
Savings & compound interest calculator
Find out how much your savings could grow. Enter a starting balance, a monthly deposit and an expected rate, and see the balance year by year, split between money you put in and interest earned.
- Enter your numbersDefaults are realistic examples; replace them with yours.
- Read results instantlyEverything updates as you type. Nothing is sent anywhere.
- Check the assumptionsSee exactly how we calculate, below.
Year-by-year schedule
Totals per year.
How we calculate
B(m) = B(m−1) × (1 + r) + deposit, r = annual rate / 12
- Interest compounds monthly; deposits are made at the end of each month.
- Rate is constant; taxes and inflation are not deducted.
Understanding your results
The longer the horizon, the larger the share of the balance that comes from interest rather than deposits. That's compounding at work.
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Frequently asked questions
What is compound interest?
Interest earned on both your deposits and on interest already earned, so growth accelerates over time.
What rate should I use?
For a high-yield savings account, use its current APY. For stock investments, many planners use 5–7% after inflation as a cautious long-run estimate.
Does this include taxes?
No. Interest in taxable accounts is taxed; in IRAs or 401(k)s it can grow tax-deferred.