Percentage Change Calculator
Two related jobs on one page. % Change compares a start value with an end value and tells you the percent it moved and whether that’s an increase or a decrease. Increase / Decrease goes the other way: take a value, add or subtract a percent, and see the new total — the way a raise, a markup, or a discount is applied.
How to calculate percentage change
Take the difference between the two values, divide by the starting value, and multiply by 100:
change % = (end − start) / |start| × 100
A positive result is an increase; a negative result is a decrease. The starting value is always the base, which is why going from 80 to 100 (+25%) and from 100 to 80 (−20%) give different percentages.
- Price rises from $80 to $100: (100 − 80) / 80 × 100 = +25%.
- Traffic falls from 5,000 to 4,000: (4,000 − 5,000) / 5,000 × 100 = −20%.
- Score goes from 45 to 54: (54 − 45) / 45 × 100 = +20%.
How to calculate a percentage increase
Multiply the base value by 1 + percent / 100. A 12% increase multiplies by 1.12; the added amount on its own is base × percent / 100.
- $500 salary, +12%: 500 × 1.12 = $560 (a $60 raise).
- 1,200 users growing 8%: 1,200 × 1.08 = 1,296.
| Increase | Multiplier | 100 → | 250 → |
|---|---|---|---|
| +5% | × 1.05 | 105 | 262.5 |
| +10% | × 1.10 | 110 | 275 |
| +20% | × 1.20 | 120 | 300 |
| +25% | × 1.25 | 125 | 312.5 |
| +50% | × 1.50 | 150 | 375 |
| +100% | × 2.00 | 200 | 500 |
How to calculate a percentage decrease
Multiply the base value by 1 − percent / 100. A 25% decrease multiplies by 0.75; the amount removed is base × percent / 100.
- $80 jacket, 25% off: 80 × 0.75 = $60 (you save $20).
- $2,400 budget cut 15%: 2,400 × 0.85 = $2,040.
| Off | Multiplier | 100 → | 250 → |
|---|---|---|---|
| 5% off | × 0.95 | 95 | 237.5 |
| 10% off | × 0.90 | 90 | 225 |
| 20% off | × 0.80 | 80 | 200 |
| 25% off | × 0.75 | 75 | 187.5 |
| 50% off | × 0.50 | 50 | 125 |
| 75% off | × 0.25 | 25 | 62.5 |
Percentage change reference
| From → To | Change |
|---|---|
| 100 → 110 | +10% |
| 100 → 125 | +25% |
| 100 → 150 | +50% |
| 100 → 200 | +100% |
| 100 → 90 | −10% |
| 100 → 75 | −25% |
| 100 → 50 | −50% |
| 80 → 100 | +25% |
| 100 → 80 | −20% |
Frequently asked questions
What is the difference between percentage change and percentage difference?
Percentage change has a direction: it measures a move from an earlier value to a later one, using the earlier value as the base. Percentage difference has no direction and divides the gap between two values by their average.
How do I add a percentage to a number?
Convert the percent to a multiplier by adding it to 1: 12% becomes 1.12. Multiply the base by that multiplier. 500 x 1.12 = 560.
How do I take a percentage off a price?
Subtract the percent from 100, convert to a decimal, and multiply. For 25% off an $80 price: 100 - 25 = 75%, so 80 x 0.75 = $60.
Why isn't a 25% increase cancelled by a 25% decrease?
Because the base changes. 80 increased by 25% is 100, but 100 decreased by 25% is 75, not 80. Each percentage is taken from a different starting number.
How do I reverse a percentage increase or discount?
Divide by the multiplier, do not subtract the percent. A $560 price after a 12% increase started at 560 / 1.12 = $500; a $60 price after 25% off started at 60 / 0.75 = $80.