Work out percentages, increases and decreases in seconds. Enter your numbers and get the answer with the working shown.
Percentage Calculator
Solve any percentage problem in one place: find a percentage of a number, find what percent one number is of another, or calculate percentage increase, decrease, and symmetric difference.
Choose your percentage mode
Switch between X% of Y, X is what % of Y, and % Change / Difference.
Your result will appear here
Enter your values above, then press Calculate Percentage — or press Enter in any field.TinyExe · Percentage Result
Exact percentage, net change & step-by-step breakdown
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Input B
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Computed Value
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Percentage change measures directional shift from a starting baseline; symmetric percentage difference divides by the average of the two values.
Common percentage benchmarks
Quick reference equivalents between percentages, decimals, and reduced fractions.
| Percentage | Decimal Factor | Reduced Fraction |
|---|---|---|
| 10% | 0.10 | 1/10 |
| 20% | 0.20 | 1/5 |
| 25% | 0.25 | 1/4 |
| 33.33% | 0.3333… | 1/3 |
| 50% | 0.50 | 1/2 |
| 75% | 0.75 | 3/4 |
The formula
Three core equations power all percentage calculations.
Percentage of a Number & Share
Convert a percentage P to a decimal by dividing by 100, then multiply by the base number Y.
Percentage Change & Difference
Positive values indicate a percentage increase; negative values indicate a percentage decrease.
Worked examples
One worked example for each of the three calculator modes.
Example 1 · X% of Y
15% of 240
Working out a 15% tip or discount on 240.
| Calculation | Steps |
|---|---|
| 15 ÷ 100 = 0.15 | Convert 15% to a decimal multiplier. |
| 0.15 × 240 = 36 | Multiply by the base amount. |
36
Example 2 · Share %
45 is what % of 180?
Finding the percentage share of a total.
| Calculation | Steps |
|---|---|
| 45 ÷ 180 = 0.25 | Divide part by whole. |
| 0.25 × 100 = 25% | Multiply by 100 to express as a percent. |
25%
Example 3 · % Change
From 120 to 150
Calculating percentage growth.
| Calculation | Steps |
|---|---|
| 150 − 120 = +30 | Net change is +30. |
| (30 ÷ 120) × 100 = +25% | 25% increase over the starting value. |
+25% Increase
How to use this calculator
Pick your calculation mode
Select X% of Y, X is what % of Y, or % Change using the switch at the top.
Enter the two numbers
Type your values into the two input boxes.
Press Calculate Percentage
View the answer, the complement or symmetric percentage difference, and the step-by-step breakdown.
Keep or share your reading
Save a branded PDF/PNG result card or pin multiple comparisons to the session tape.
Frequently asked questions
How do I calculate a percentage increase?
Subtract the original value from the new value, divide that difference by the original value, and multiply by 100.
Why doesn't a 10% increase followed by a 10% decrease return to the original number?
Because the 10% decrease applies to the larger increased number (1.10 × 0.90 = 0.99, or 99% of the original value).
What is the difference between percentage change and percentage points?
Moving from 10% to 15% is a 5 percentage-point increase, but a 50% relative percentage increase.