Percentage Calculator

Calculate percentages 6 different ways — each calculator shows the formula so you understand how it works.

X% of Y · What % is X of Y · % Change · % Increase/Decrease · Add/Subtract % · % Difference
Quick Examples — click to fill
15% of 200
7.5% of 85
45 is what % of 180
% change 80→100
250 + 20%
$199 minus 15%
% diff 85 vs 110
%Percentage Calculators
1 — Find X% of a Number
What is 15% of 200?
What is % of ?
2 — X is What % of Y?
45 is what % of 180?
is what % of ?
3 — Percent Change
From old value to new value
From to
4 — Add a Percentage
Price + tax/tip/markup
+ %
5 — Subtract a Percentage
Price after discount
− %
6 — Percent Difference
Difference between two values
Between and

Reference

Percentage formulas quick reference

Find X% of Y
Result = Y × (X ÷ 100)
15% of 200 = 200 × 0.15 = 30
What % is X of Y?
% = (X ÷ Y) × 100
45 ÷ 180 × 100 = 25%
% Change
((New − Old) ÷ Old) × 100
(100 − 80) ÷ 80 × 100 = +25%
Add / Subtract %
N × (1 + P/100) or N × (1 − P/100)
200 + 15% = 200 × 1.15 = 230
% Difference
|V1 − V2| ÷ ((V1+V2)÷2) × 100
|85 − 110| ÷ 97.5 × 100 = 25.6%
Common Conversions
1% = ÷100
10% = ÷10
25% = ÷4
50% = ÷2
20% = ÷5
33.3% = ÷3

FAQ

Percentage questions answered

How do I calculate a percentage of a number?
Multiply the number by the percentage divided by 100. 15% of 200 = 200 × (15÷100) = 200 × 0.15 = 30. Mental math shortcut: 10% is just moving the decimal left one place. 10% of 250 = 25. Then 15% = 25 + 12.5 = 37.5.
What is the percent change formula?
Percent Change = ((New − Old) ÷ Old) × 100. If something goes from $80 to $100: ((100−80)÷80)×100 = +25%. From $100 to $80: ((80−100)÷100)×100 = −20%. The base is always the OLD value.
Percent change vs percent difference — which do I use?
Use percent change when one value is the baseline (before/after, old/new). Use percent difference when comparing two independent values with no clear baseline. Percent difference uses the average of both values as the denominator.
How do I reverse a percentage (find the original price before a discount)?
If $170 is the price after a 15% discount, the original price = $170 ÷ (1 − 0.15) = $170 ÷ 0.85 = $200. Don't subtract the percent from the discounted price — that gives the wrong answer. Always divide by (1 − discount rate).