The formulas
| X% of Y | Y × X ÷ 100 |
| X is what % of Y | X ÷ Y × 100 |
| % change from A to B | (B − A) ÷ |A| × 100 |
| Y increased by X% | Y × (1 + X ÷ 100) |
| Y decreased by X% | Y × (1 − X ÷ 100) |
| % difference | |A − B| ÷ ((A + B) ÷ 2) × 100 |
Examples
- A $80 item with 25% off costs $60 (decrease by 25%).
- Rent going from $1,500 to $1,650 is a +10% change.
- A 15% tip on $64 is $9.60 (15% of 64).
Why this one?
- No sign-up, no limits. Use it as much as you like.
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Related tools
FAQ
What’s the difference between percent change and percent difference?
Percent change has a direction (from old to new). Percent difference compares two values without a “before” and “after”, relative to their average.
How do I reverse a percentage increase?
Divide by (1 + the percentage). A price of 115 after a 15% increase was 115 ÷ 1.15 = 100 before.