Simple Interest Calculator

Interest and total amount from principal, rate and time — the I = P × R × T formula.

FREE TOOL · WORKS OFFLINE · NO SIGN-UP

Results update instantly as you type. Half years are fine: 2.5 means two years and six months.

Total amount
$0
Interest
$0
Principal
$0
Interest per year
$0

💵 How to Use This Simple Interest Calculator

  1. 1.Enter the principal. That is the amount borrowed or invested at the start, before any interest.
  2. 2.Enter the yearly rate. Use the annual percentage from the loan or account — for example, 5 for 5%.
  3. 3.Set the time in years. The formula needs years, and decimals work: 1.5 years is eighteen months.
  4. 4.Read the interest and the total. The total is the principal plus all the interest over the full period.
  5. 5.Compare with compounding. If the money compounds instead, the real total will be higher than this figure — simple interest is the floor, not the ceiling.

❓ FAQ

What is the simple interest formula?

Interest = Principal × Rate × Time, where the rate is the yearly percentage divided by 100 and the time is measured in years. The total amount is the principal plus the interest. For example, $5,000 at 5% for 3 years earns $5,000 × 0.05 × 3 = $750 of interest, for a total of $5,750.

Where is simple interest used?

Simple interest shows up in many car loans, short-term personal loans, some bonds and savings products, and in late-payment penalties. Mortgages and credit cards work differently — mortgages amortize month by month, and credit cards charge interest on the daily balance.

How is simple interest different from compound interest?

Simple interest is always calculated on the original principal only, so it grows by the same amount every year. Compound interest is calculated on the principal plus the interest already earned, so it grows faster and faster over time.

Is this simple interest calculator free?

Yes — 100% free, no sign-up, no limits. Everything runs in your browser; none of your numbers are uploaded or saved.

← More free tools