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Finance

Simple Interest Calculator

Find interest earned on a fixed principal without compounding.

Amounts stay on this deviceMethod and assumptions below

Your financial inputs

Runs on your device

YOUR FINANCIAL SUMMARY

Your result

Let’s calculate.

Use the Calculate button to see your result.

Estimate based on your inputs and the stated assumptions.

How to use this tool

  1. Enter principal, annual rate, term.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Interest = principal × annual rate ÷ 100 × years. Final balance = principal + interest. Unlike compound interest, interest is not added to the amount earning interest.

A WORKED EXAMPLE

A principal of 1,000 at 5% per year for 3 years earns 150. The final balance is 1,150.

What to keep in mind

Assumes a constant rate and no principal repayments, fees or taxes. Enter 0.5 years for six months. Actual contracts may use specific day-count conventions.

Common questions

How does this differ from compound interest?

Simple interest always uses the original principal. Compound interest can earn further interest on earlier interest.

Can I use it for a repayment loan?

Not directly. A loan with a declining balance needs its actual repayment schedule; this tool keeps the principal constant.

Methodology maintained by ClarityKit. How these tools are built and checked.