Percentage Calculator — Free Online Percent Calculator
Four common percentage calculations — results update instantly.
What is X% of Y?
e.g. What is 20% of 150? → 30
X is what % of Y?
e.g. 30 is what % of 150? → 20%
Percentage change
e.g. from 80 to 100 → +25%
Increase / decrease by %
e.g. 200 increased by 15% → 230 / decreased → 170
About the Percentage Calculator
Percentages show up everywhere — discounts, tax, tips, test scores, interest rates, budgets. This calculator covers the four most common percentage questions, so you never have to remember the formula.
The four calculations explained
X% of Y = (X ÷ 100) × Y
X is ?% of Y = (X ÷ Y) × 100
% change = ((New − Old) ÷ |Old|) × 100
Increase by X% = Number × (1 + X ÷ 100)
Real-world examples
- 🛍️20% off a $85 item → 20% of 85 = $17 discount → you pay $68
- 📈Stock went from $120 to $156 → % change = +30%
- 🍽️18% tip on a $47 meal → 18% of 47 = $8.46
- 📊Scored 43 out of 50 → 43 is what % of 50 = 86%
Related: Unit Converter for measurement conversions, or Break-even Calculator for business margin analysis.
Frequently Asked Questions
Is the Percentage Calculator free?
Yes — completely free. No account and no data sent to a server.
Do I need an account?
No account, no login, and no signup required.
What types of percentage calculations does it support?
Four modes: What is X% of Y (tip and discount), X is what percent of Y (comparing a part to a whole), X is Y% of what (working backward from a percentage), and percentage change from X to Y (before-and-after comparison).
Why is 50% off then 20% off not the same as 70% off?
The second discount applies to the already-reduced price, not the original. At 50% off, $100 becomes $50. Then 20% off $50 is $10, leaving $40 — a 60% total discount, not 70%. Stacked discounts are always less than their sum.