Percentage Calculator

Calculate percentages easily
This free online percentage calculator runs in your browser and is part of our Calculators collection.

🧮 Percentage Calculator

Calculate percentages easily

What is X% of Y?

X is what % of Y?

Percentage Change

Increase/Decrease by %

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Instant In-Browser Execution Runs locally in JavaScript without wait times or server delays.
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100% Privacy & Security Your inputs and files are never stored or logged on remote servers.
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Cross-Device Responsive Fully optimized for mobile smartphones, tablets, and desktop displays.
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100% Free Forever No subscription fees, no signups, and no software installations.

How to Use the Online Percentage Calculator

1 Select Calculation Type

Choose your percentage question: "What is X% of Y?", "X is what percentage of Y?", or "Percentage increase/decrease from X to Y".

2 Enter Values

Type your numbers into the corresponding fields (e.g. 15% of $80, or change from 50 to 75).

3 Review Instant Calculation

The calculator computes answers in real time as you type, highlighting the exact percentage and difference.

4 Inspect Mathematical Formula

View the step-by-step mathematical breakdown showing exactly how the formula was solved.

Frequently Asked Questions

Common questions about using this free online percentage calculator.

How is percentage increase or decrease calculated? ▾
Percentage change is calculated as: `((New Value − Old Value) / |Old Value|) × 100`. A positive result indicates percentage growth; a negative result indicates a percentage decrease.
How do I calculate sales tax or discount on an item? ▾
Use the "What is X% of Y?" tab. For a 20% discount on an $80 item, enter 20% and 80 to get $16 discount (final price = $80 − $16 = $64). For an 8% tax, enter 8% and 80 to get $6.40 tax (final price = $86.40).
Can I enter negative numbers or decimal percentages? ▾
Yes. The calculator fully supports negative base numbers and fractional percentages (e.g. 3.75%).
What is the formula for "X is what percentage of Y"? ▾
The formula is `(X / Y) × 100`. For example, 25 out of 200 equals (25 / 200) × 100 = 12.5%.

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