About the Percentage Calculator
Five percentage modes, live results, and step-by-step working — all in one free tool.
What it is
The Percentage Calculator covers the five most common percentage problems in one place. Pick the type of calculation you need, enter your numbers, and the result appears instantly — along with the equation used, so you can verify or learn the method.
Everything runs in your browser. No data is sent to a server or stored anywhere.
Five calculation modes
X% of Y
Find a percentage of any number. Formula: P ÷ 100 × Y. Example: 20% of 80 = 16.
What % is X of Y?
Find what percentage the part is of the whole. Formula: X ÷ Y × 100. Example: 16 of 80 = 20%.
Percentage Change
Find the % increase or decrease between two values. Formula: (B − A) ÷ A × 100. Example: 80 → 100 = +25%.
Add / Subtract %
Apply a percentage on top of or off a number. Add: Y × (1 + P/100). Subtract: Y × (1 − P/100). Useful for discounts, tips, tax, and markups.
Reverse %
Find the original whole when you know a part and its percentage. Formula: X ÷ (P ÷ 100). Example: 16 is 20% of 80.
Common uses
Shopping & discounts
Calculate sale prices, discount amounts, or what percentage off a deal really is.
Test scores
Convert a raw score to a percentage, or find the score needed to reach a target.
Tips & tax
Add a tip percentage to a bill, or work out tax on a price before or after.
Finance & growth
Calculate return on investment, revenue growth, or budget changes as a percentage.
Nutrition & goals
Find what percentage of a daily target a serving represents, or hit a macro target.
Data & reporting
Express changes in figures as percentages for reports, charts, and presentations.
Completely free
No account, no install, no limits. Open the tool and start calculating — it works on desktop and mobile.