Interest Calculator

Calculate both simple and compound interest with our easy-to-use calculator. Plan your investments and savings with accurate interest calculations.

Simple Interest Calculator

Calculate interest earned on principal amount only

Simple Interest Results

$0.00
Interest Amount
$0.00
Total Amount

Compound Interest Calculator

Calculate interest on principal plus accumulated interest

Compound Interest Results

$0.00
Interest Amount
$0.00
Total Amount

How to Calculate Interest

Learn the difference between simple and compound interest and how to calculate them

1

Simple Interest

Simple interest is calculated only on the principal amount. Use the formula: I = P × R × T, where I is interest, P is principal, R is rate, and T is time.

2

Compound Interest

Compound interest is calculated on the principal amount and also on the accumulated interest. Use the formula: A = P(1 + r/n)nt, where A is total amount, P is principal, r is rate, n is compounding frequency, and t is time.

3

Key Differences

Simple interest grows linearly while compound interest grows exponentially. For long-term investments, compound interest yields significantly higher returns due to the "interest on interest" effect.

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Why Use Our Interest Calculator?

Our calculator provides accurate results with these powerful features

Instant Results

Get immediate calculations for both simple and compound interest with our fast, responsive calculator.

Privacy Focused

All calculations happen locally in your browser. We never store or transmit your financial data.

Dual Calculator

Calculate both simple and compound interest side by side to compare results and make informed decisions.

Fully Responsive

Use our calculator on any device - desktop, tablet, or mobile - with a perfect experience.

Completely Free

All our calculators are 100% free to use with no hidden costs or premium tiers.

Detailed Breakdown

Get a complete breakdown of interest earned and total amount for better financial planning.

Frequently Asked Questions

Find answers to common questions about interest calculations

What is the difference between simple and compound interest?
Simple interest is calculated only on the principal amount, while compound interest is calculated on the principal amount plus any accumulated interest. This means compound interest grows faster over time because you earn "interest on interest."
How often should interest be compounded for maximum returns?
The more frequently interest is compounded, the higher the returns. Daily compounding yields the highest returns, followed by monthly, quarterly, semi-annually, and annually. However, the difference becomes more significant over longer time periods.
Can I use this calculator for both investments and loans?
Yes, our interest calculator works for both scenarios. For investments, it shows how much your money will grow. For loans, it shows how much interest you'll pay over the loan term.
Is the interest calculated before or after taxes?
Our calculator shows pre-tax interest amounts. The actual returns on investments or cost of loans may vary based on your tax situation. Consult with a financial advisor for tax-specific calculations.
How accurate are the calculations?
Our calculator uses standard financial formulas for simple and compound interest, providing highly accurate results. However, actual financial products may have additional fees or variations not accounted for in these basic calculations.

Ready to Calculate Your Interest?

Use our accurate interest calculator to plan your investments and savings

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