Percentage Calculator
Calculate X% of a number, find what percent one value is of another, reverse a percentage, compare percentage change, and work out percentage difference, discounts, increases, and decreases.
Select Scenario
Result
30
Formula
20% of 150 = 30
percentage ÷ 100 × value
Result
13.3333%
Formula
20 is 13.3333% of 150
part ÷ whole × 100
Result
13.3333
Formula
20 is 150% of 13.3333
part ÷ percentage × 100
Result
650%
Formula
20 to 150 = 650% increase
(new value - original value) ÷ original value × 100
Change amount
130
Baseline
20
Result
180
Formula
150 plus 20% = 180
value × (1 + percentage ÷ 100)
Percentage amount
30
Result
120
Formula
150 minus 20% = 120
value × (1 - percentage ÷ 100)
Percentage amount
30
Reverse from
Result
-40
Formula
20 after 150% decrease started at -40
final value ÷ (1 - percentage ÷ 100)
Difference from original
60
Result
152.9412%
Formula
20 and 150 differ by 152.9412%
|first value - second value| ÷ average(|first value|, |second value|) × 100
Absolute difference
130
Average baseline
85
Common Scenarios
Basic
Change
Compare
Quick Start
Common Scenarios
Use this for questions like "what is 20% of 150?" to turn a percentage into a number.
Use this for shares, completion rates, ratios, and questions like "30 is what percent of 150?"
Use this for questions like “30 is 20% of what?” when you know the part and the percent but not the whole.
Compare an old value and a new value to see the relative increase or decrease.
Use this for markup, growth, tax, tips, or any value raised by a percentage.
Use this for discounts such as 20% off, price cuts, deductions, or values reduced by a percentage.
Use this when you know the final value after a percentage increase or decrease and need the original value.
Compare two values symmetrically using the average of their absolute values as the baseline.
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FAQ
Choose percent of a value when the question is phrased like “what is 20% of 150?” The formula is percentage / 100 × value, so 20 / 100 × 150 = 30.
Use part as a percent of whole. Enter the part first and the whole second; 30 out of 150 is 20%.
Use find the whole. For “30 is 20% of what?”, the calculator computes 30 ÷ 20 × 100 = 150.
It uses the original value as the baseline: (new value - original value) ÷ original value × 100. If the original value is 0, the percentage change is undefined; use percentage difference only when neither value should be treated as the baseline.
Use subtract percentage for a sale price: 20% off 150 returns 120. If you already know the sale price, use reverse percentage with after decrease / discount; 80 after 20% off means the original price was 100.
Percentage points are the direct gap between two percentages. Percent change is relative to the starting value, and compound changes use a new base each step: a 20% decrease needs a 25% increase to return to the original value.