Find a percentage or share
Use the percentage calculator for a percentage of an amount or to find what percentage one value represents of another. Check which value is the whole before interpreting the result as a share or proportion.
Maths and number tools
Choose the calculation before entering the numbers. A percentage of an amount, a change from an original value and a ratio between dimensions answer different questions.
What do you want to do?
Compare a before-and-after value
Choose percentage change for a comparison against an original value, or an increase or decrease when applying a known rate. Symmetric percentage difference is a separate comparison and should not be substituted for a directional change.
Plan proportional dimensions
Use the aspect ratio calculator to reduce a width-to-height ratio, calculate a missing proportional dimension, or estimate centered padding and cropping. Use the image guide when you are ready to edit the actual picture.
All available Maths and number tools
Before you start
Check the reference value
Increasing a value by a percentage and then decreasing it by the same percentage generally does not restore the original. A percentage change from zero has no ordinary percentage baseline.
Pixel dimensions need whole numbers
A proportional dimension may require rounding when used as a pixel count. Review the disclosed rounding and resulting ratio before exporting; calculating dimensions does not resize an image.
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