Percentage Calculator

中

Loading...

Percentage Calculator — Increase, Decrease, Of and Change

Five percentage calculations in one tool, switched by a single click: X% of Y, X increased by Y%, X decreased by Y%, X is what percent of Y, and the percent change from X to Y. No formulas to remember, no misremembered order of operations.

Use it for discounts and markups, tips and taxes, grade percentages, growth rates, and comparing before/after values. Each mode labels exactly which number is which — the classic source of percentage mistakes.

How to calculate percentages

  1. Pick the calculation type — the labels change to match it.
  2. Enter the two numbers in the labeled fields.
  3. Read the result instantly; percent-type results include the % sign.
  4. Switch types freely — inputs are kept.

Frequently asked questions

What is the difference between "X is what % of Y" and "% change"?

"30 is what % of 150" asks for a share of a total (20%). "% change from 150 to 200" asks for relative movement between two values (+33.3%). Same numbers, different question — using the wrong one is the most common percentage error.

How do I apply a percentage increase then decrease?

They do not cancel: 100 +10% = 110, then −10% = 99. Each percentage applies to the current value, not the original. Chain the operations with this tool to see the real result.

Why does a percent change from 0 fail?

Percentage change is relative to the starting value; from zero the change is undefined (any result is "infinitely larger"). The tool reports this instead of showing a misleading number.

Related tools

Date Calculator
Days between two dates, or add/subtract days from a date
Unit Converter
Convert length, weight, temperature, area, volume, and speed units
Base Converter
Convert between binary, octal, decimal, hexadecimal, and ASCII

PureKit · percentage-calculator · Free online tool — files processed locally in your browser, no upload.