Free growth calculator
Compound Interest Calculator
Estimate how principal, monthly contributions, time, and compounding frequency can change a balance. Compare future outcomes side by side so the range feels visible, not abstract.
Popular calculators
Use the version that matches your question.
Each page keeps the math narrow so you can compare results without digging through a spreadsheet.
Monthly Compound Interest Calculator
Use for savings plans, monthly deposits, and long-term contribution schedules.
Daily Compound Interest Calculator
Estimate balances when a bank account or product compounds every day.
Savings Goal Calculator
Find the monthly contribution needed to aim for a target balance.
APY Calculator
Convert a nominal rate and compounding frequency into annual percentage yield.
Compound Interest Formula
See the formulas for one-time principal and recurring contributions.
Interest vs Contributions
Separate what you put in from what the growth assumption adds.
Core formula
How this calculator estimates growth
For the main tool, monthly contributions are added at the end of each month. The selected annual compounding frequency is converted into an effective monthly growth rate.
monthlyRate = (1 + r / n) ^ (n / 12) - 1balance = balance * (1 + monthlyRate) + contributionWhere r is the nominal annual rate and n is the number of compounding periods per year.