Simple Interest Calculator
The simple interest calculator helps you quickly calculate interest earned, total return, and overall rate across a time period.
Unlike compound interest, simple interest is calculated only on the original principal, making it easier to understand and predict.
This makes it useful for basic loans, short-term investments, and educational calculations.
Use this calculator to see how your money grows over time without compounding.
Calculate simple interest
Understanding your result
The interest shown is the total amount earned over the entire period.
Because simple interest does not compound, the growth is linear and predictable.
The final amount represents your original investment plus the interest earned.
How simple interest works
Formula: Interest = Principal × Rate × Time
This means the same amount of interest is earned each year.
Unlike compound interest, you do not earn interest on previously earned interest.
Examples
Example 1:
£1,000 at 5% for 3 years → £150 interest → £1,150 total
Example 2:
£500 at 8% for 2 years → £80 interest → £580 total
Example 3 (Comparison):
Simple interest grows slower than compound interest over time.
Simple vs compound interest
Simple interest is easier to calculate but results in lower returns compared to compound interest.
Compound interest grows faster because it includes interest on accumulated interest.
Understanding this difference is important when comparing savings, loans, and investments.
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Frequently asked questions
What is simple interest?
Interest calculated only on the original amount.
Is simple interest used in real life?
Yes, for some loans and short-term agreements.
Which is better: simple or compound?
Compound is better for growth; simple is easier to calculate.