Simple and compound interest calculator
Estimate simple or compound interest from principal, annual rate, years and compounding frequency. See both interest and total amount.
Ready when you are.
Illustrative arithmetic only. Assumes a constant annual nominal rate, no deposits, withdrawals, fees or tax. Actual products may use different accrual and rounding rules.
How to use this tool
- Enter principal, annual rate and time in years.
- Choose simple interest or a compounding frequency.
- Review interest earned and total amount.
Frequently asked questions
What formulas are used?
Simple amount = P × (1 + r × t / 100). Compound amount = P × (1 + r / (100 × n))^(n × t), where n is periods per year.
Can I use a fraction of a year?
Yes. For compound interest, fractional periods use the power formula; actual accounts may handle partial periods differently.
Does this include tax or fees?
No. It is a mathematical estimate, not a quote for a deposit or loan.