Percentage Calculator
Calculate percentages, proportions, percentage increase, decrease, and differences instantly in your browser.
What is X% of Y?
Calculate a specific percentage of any number (e.g. tips, sales tax, discounts).
15% of 80 is 12
Result = (X / 100) × Y- 1. Convert percentage to decimal: 15 ÷ 100 = 0.15
- 2. Multiply by base number: 0.15 × 80 = 12
Percentage Formula Reference Table
| Calculation | Mathematical Formula | Example Scenario |
|---|---|---|
| What is X% of Y? | (X ÷ 100) × Y | 15% tip on a $60 dinner = $9 |
| X is what % of Y? | (X ÷ Y) × 100 | Score 42 out of 50 = 84% |
| Percentage Change | ((To - From) ÷ |From|) × 100 | Price rises from $100 to $125 = +25% |
| Percentage Difference | (|A - B| ÷ ((A + B) ÷ 2)) × 100 | Comparing $40 vs $50 = 22.22% difference |
How it works?
Select Calculation Mode
Choose whether you want to find a percentage of a total, determine proportion, compute percentage change, or compare two values.
Enter Numeric Values
Type your values into the respective fields or click quick preset buttons for common discount or tax percentages.
Instant Live Calculation
Your browser calculates the exact result instantaneously with full floating-point precision and zero server communication.
Inspect Formula & Copy
Review the step-by-step arithmetic breakdown, customize decimal places, and copy the result with one click.
Tips & Best Practices
- •Calculate Discounts Instantly: To find the final price during a sale, calculate what X% is of the original price, then subtract it. For example, 20% off $80 is $16 savings, so you pay $64.
- •Understanding Percentage Change vs Points: If an interest rate moves from 5% to 6%, that is a 1 percentage point increase, but a 20% relative percentage increase in the rate itself.
- •Reverse Percentage Math: X% of Y is always equal to Y% of X. For example, calculating 8% of 50 in your head is tricky, but 50% of 8 is simply 4!
- •100% Client-Side Privacy: All financial figures, salaries, markups, or tax data remain confidential on your device without leaving your browser.
Related Tools You Might Find Useful
Explore complementary utilities designed to speed up your workflow.
Reading Time Calculator
Estimate silent reading, speech delivery, and audiobook durations with custom WPM.
Word & Character Counter
Tally words, characters, sentences, paragraphs, and reading times client-side.
UUID Generator & Validator
Generate cryptographically secure RFC 4122 v4/v1 UUIDs with format inspectors.