Calculate percentages easily — find percentage of a number, percentage change, and more.
What is X % of Y?
A is what % of B?
Percentage Change
Result
What is X% % of Y-
A is what % of B-
Percentage Change-
⚙️ How It Works
A percentage calculator solves the most common percentage problems: finding what percent one number is of another, calculating a percentage of a number, and finding the original value when you know a percentage of it. Percentages express a ratio as parts per hundred, making comparisons between different-sized quantities easy.
% of Number: Result = (Percent / 100) × Number | What % is X of Y: Percent = (X / Y) × 100 | Original Value: Original = Value / (Percent / 100)
Editorial Standards
Author
BetterProduct Editorial Team
Reviewed by
Checked against standard math or conversion logic and browser-side calculation behavior.
Updated
March 2026
Best used for
Quick everyday calculations and unit checks.
Languages checked
English public edition reviewed against the same source formulas used in maintenance.
Use Results Responsibly
Check units and formats before you calculate.
Round only at the end if precision matters.
Use official records for deadlines, utility rates, or school policies when applicable.
❓ FAQ
How do I calculate a percentage increase?
Percentage increase = ((New Value − Old Value) / Old Value) × 100. Example: price goes from $80 to $100 → ((100 − 80) / 80) × 100 = 25% increase.
What is the difference between percentage and percentage points?
Percentage points measure the arithmetic difference between two percentages. If interest rates rise from 2% to 5%, that's a 3 percentage point increase, but a 150% relative increase. The distinction matters in finance and statistics.
How do I calculate a tip using percentages?
Multiply the bill by the tip percentage divided by 100. For a 20% tip on a $45 bill: 45 × 0.20 = $9 tip. A quick mental trick: find 10% (move decimal left one place), then double it for 20%.
What does 'per mille' mean?
Per mille (‰) means per thousand, similar to percent (per hundred). It's used in contexts where percentages are too large — like blood alcohol content (0.08% = 0.8‰) or bond yields. 1% = 10‰.