Interest Calculator

Simple interest grows only on the original principal. Compound interest grows on the principal and on interest previously added to the balance.

The calculator uses your principal, annual interest rate, time period, and compounding frequency to estimate interest earned and the final balance.

A higher rate, longer duration, or more frequent compounding can increase the ending balance. The comparison shows how these factors change the result without requiring manual calculations.

In these formulas, P is the principal, r is the annual interest rate expressed as a decimal, n is the number of compounding periods per year, and t is the time in years.

In the compound interest formula, A represents the final accumulated balance, including both the original principal and compound interest earned.

An interest calculator estimates how a starting principal can grow over time based on an annual interest rate, duration, and compounding schedule. It can be used for savings accounts, fixed deposits, investment projections, and general financial planning.

This calculator compares simple and compound interest side by side. It also displays the effective annual rate, estimated interest earned, ending balance, and a year-by-year growth schedule.

You can select the currency used to display the principal and results. You can also save several scenarios in your browser and export selected calculations.

Simple interest is calculated only on the original principal. Compound interest is calculated on the principal and accumulated interest from earlier compounding periods.

The difference may appear small over a short period, but it can become more noticeable when the rate, principal, or duration increases.

Consider a principal of $10,000.00, an annual interest rate of 5.00%, a time period of 10 years, and monthly compounding.

The calculator applies both the simple interest and compound interest formulas so the two ending balances can be compared.

More frequent compounding generally increases the ending balance because earned interest is added to the account more frequently.

The difference between monthly and daily compounding may be modest for smaller balances or shorter periods. It can become more visible when the principal, interest rate, or investment duration is larger.

An interest calculator is useful when comparing savings accounts, fixed deposits, investment projections, or other products where a principal balance may grow over time.

You can test different rates and durations to understand how each variable affects interest earned and the projected ending balance.

The saved-results table is especially useful when comparing several financial scenarios because selected calculations can be exported together as a CSV or TXT file.

This calculator is designed for educational and informational use. It estimates simple interest, compound interest, effective annual rate, and balance growth using the values you provide.

Selecting a different currency changes how the entered amount and results are displayed. It does not convert the amount using a foreign exchange rate.

Actual savings or investment results may differ because financial institutions can use different calculation methods, fees, taxes, changing rates, deposit schedules, withdrawal rules, and rounding policies.

Calculator Tools provides free finance calculators, converters, and planning tools designed to make common calculations faster and easier to understand.