6 TYPES OF PERCENTAGE CALCULATIONS · INSTANT RESULTS
① WHAT IS X% OF Y?
% of
② X IS WHAT % OF Y?
out of
③ PERCENTAGE CHANGE (INCREASE / DECREASE)
→
④ INCREASE OR DECREASE NUMBER BY %
by
⑤ DISCOUNT CALCULATOR
–
⑥ REVERSE PERCENTAGE (FIND ORIGINAL VALUE)
is
Free Percentage Calculator – Calculate Any Percentage Instantly
By RapidTool Team · Last updated: September 2026
Our free percentage calculator handles all types of percentage math in one place. Whether you need to find what percentage one number is of another, calculate a discount, find percentage increase or decrease, or reverse-calculate the original price from a percentage — our tool covers all 6 common use cases instantly.
Percentage Formulas
X% of Y
Result = (X ÷ 100) × Y
X is ?% of Y
Result = (X ÷ Y) × 100
% Change
((New − Old) ÷ Old) × 100
Reverse %
Original = Value ÷ (% ÷ 100)
Frequently Asked Questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 20% of 500 = (20 × 500) ÷ 100 = 100. Our calculator does this automatically in Calculator ①.
How do I calculate percentage increase or decrease?
Percentage change = ((New Value − Old Value) ÷ Old Value) × 100. A positive result means an increase, negative means a decrease. For example, from 80 to 100: ((100−80)÷80)×100 = 25% increase.
How do I find the original price before a discount?
Use the reverse percentage formula: Original Price = Sale Price ÷ (1 − Discount%). For example, if an item costs $75 after a 25% discount: $75 ÷ 0.75 = $100 original price. Use Calculator ⑥ for this.
What is the difference between percentage point and percentage?
A "percentage point" is an absolute difference between two percentages, while "percent" refers to a relative change. If interest rates go from 2% to 5%, that's a 3 percentage point increase, but a 150% relative increase. The distinction matters in financial and economic contexts.