Simple Interest Calculator
Simple Interest
Interest
$50.00
Total amount
$1,050.00
Annual rate
5%
How calculations work
All calculations run locally in your browser; we do not call any external APIs.
- Principal: the starting amount you enter.
- Rate: annual percentage rate (entered as %).
- Time: years the principal is invested or borrowed for.
- Interest: computed as Principal × Rate × Time.
- Total: Principal + Interest.
Values are numeric and rounded for display; this is a simple, non-compounding estimate for educational use.
What this does
The Simple Interest Calculator computes interest on a principal amount using a fixed annual rate and a set number of years. Unlike compound interest, simple interest does not reinvest interest; it is useful for short-term or straightforward interest estimates.
Who should use
Use this when you need a quick, no-frills estimate — for example short-term loans, basic interest on promissory notes, or educational examples. If your situation involves reinvested earnings, use the compound interest calculator instead.
How this works
The formula used is Interest = Principal × Rate × Time (with rate as a decimal). The total amount is Principal + Interest. Inputs are treated as numeric and the rate is interpreted as an annual percentage.
How to interpret the results
The output shows the interest earned over the period and the resulting total. Use different inputs to compare scenarios or to back-calculate a required rate or time to meet a target amount.
Example
For a $2,000 principal at 4% for 3 years, simple interest is $240 and the total is $2,240. This illustrates how simple interest compares to compound returns over short horizons.
Limitations & disclaimer
This tool assumes constant rates and ignores compounding, taxes and fees. It is for informational use only. See the calculators hub for other calculators and localized formats.