Savings & compound interest calculator
Grow savings with monthly contributions and compound returns.
Estimate for information only — not financial, tax, legal or medical advice.
How it's calculated
Balance grows by periodic rate (annual rate ÷ compounds per year) at each compounding period; contributions are added at the start of each month.
- Constant rate
- No taxes or fees
- Contributions at the start of each month
Version 1.0 · exact decimal maths · inputs are not stored.
Questions
What return should I assume?
Use a conservative figure. Bank savings, National Savings certificates and mutual funds all have different and changing returns, and inflation reduces real value.
Does compounding frequency matter much?
Monthly versus yearly compounding makes a modest difference; the rate, time and contribution amount matter far more.