% Math Calculator

Percentage Calculator

Calculate percentages in any direction — find a percentage of a number, what percent one number is of another, or calculate percentage increase/decrease between two values.

Choose Calculation Type

Percentage (%)

of Number

Choose a calculation type above

Three modes: % of a number, "X is what % of Y", and % change.

Quick Reference

Type	Formula
P% of N	N × P ÷ 100
X is ?% of Y	X ÷ Y × 100
% Increase	(New − Old) ÷ Old × 100
% Decrease	(Old − New) ÷ Old × 100

Frequently Asked Questions

How do I find 15% of 200?

Use the formula: Value × Percentage ÷ 100 = 200 × 15 ÷ 100 = 30. Shortcut: Move the decimal left to get 10% (20), then halve it for 5% (10), add: 20 + 10 = 30.

How do I calculate percentage change?

Percentage Change = (New Value − Old Value) ÷ Old Value × 100. If the result is positive, it's an increase. If negative, it's a decrease. Example: from 80 to 100 = (100−80)÷80×100 = 25% increase.