Percentage calculator
Most percentage questions are one of five shapes. Pick the one you need and the figures follow, with the formula shown.
Result50.00
- Remainder
- 200.00
- Starting value
- 250.00
The formula
X% of Y = X · Y / 100. X as a share of Y = X / Y × 100. Change from X to Y = (Y − X) / X × 100. Adding or removing X% multiplies by (1 ± X / 100).
Worked example
20% of 250 is 50. Going from 250 to 300 is a 20% rise; going back from 300 to 250 is a 16.67% fall.
How to use it
- 1Choose the mode first — it decides what X and Y mean.
- 2For a change, X is the starting value and Y is the new one.
- 3A rise and the matching fall are never the same percentage.
Questions people ask
Why isn't a 20% rise cancelled by a 20% fall?
Because the second percentage is taken from a bigger number. 100 rises to 120, and 20% off 120 is 96, not 100.
What is the difference between percent and percentage points?
Going from 4% to 6% is a rise of two percentage points, but a 50% increase. Headlines mix the two constantly.
Last reviewed: 2026-10-20