Percentage Calculator
Solve 6 types of percentage problems instantly: find a percentage, percentage change, percentage of total, increase/decrease, and reverse percentage.
6 Calculation Types⚡ Instant
% Percentage Calculator
Results update instantly
What is X% of Y?
%
of
= 30
X is what % of Y?
is what % of
= 15%
Percentage Change
→ new value →
= +25%
Increase/Decrease by %
%
+Increase
−Decrease
= 240
Percentage Formulas — All Types Explained
Percentages appear everywhere in everyday life: discounts, tax rates, interest rates, grade calculations, statistics, and financial analysis. Here are the core formulas:
📐 Core Percentage Formulas
X% of Y = (X ÷ 100) × Y
X of YPercentage of a number: (X/100) × Y
X is %What % is X of Y: (X ÷ Y) × 100
Change% change: ((New − Old) ÷ Old) × 100
ReverseOriginal value: Amount ÷ (1 + rate)
Frequently Asked Questions
Multiply the number by 0.20 (or divide by 5). For example, 20% of $150 = $150 × 0.20 = $30. A quick mental trick: find 10% (move decimal one place left), then double it.
Subtract the old value from the new value, divide by the old value, and multiply by 100. Formula: ((New − Old) ÷ Old) × 100. If the result is positive, it is an increase; if negative, a decrease.
Use reverse percentage: Original = Sale price ÷ (1 − discount%). For example, if an item costs $80 after a 20% discount: Original = $80 ÷ 0.80 = $100.
⚠️ Disclaimer Estimates for informational purposes only. Not legal or financial advice. Consult a qualified professional.