Percentage Calculator
Solve every common percentage question: X% of Y, X is what % of Y, and percent change.
Free · No sign-up · Runs locally in your browser · Also available in Chinese (中文)
What is Percentage Calculator?
A percentage calculator answers the small set of questions that cover almost every real-world percentage problem: what is X percent of Y, X is what percent of Y, and what is the percentage increase or decrease from one value to another. Instead of rearranging formulas on paper, you type two numbers and get the answer.
Percentages appear everywhere — discounts, taxes, tips, exam scores, growth rates and commission splits. The tool computes each variant with full decimal precision and rounds only at display time, which avoids the classic rounding-error traps of doing it by hand.
How to use it
- 1Choose the question form that matches your problem (find X% of Y, or find what percent X is of Y).
- 2Enter the two known values in the input fields.
- 3Read the answer immediately — no calculate button needed.
- 4Use the percent-change mode to compare an old value against a new one.
Common use cases
- Working out a 15% tip or a 30% discount while shopping.
- Comparing this month's revenue to last month's as a percentage change.
- Checking what share of a project budget a single line item represents.
Frequently asked questions
▸What is the difference between percentage points and percent?
If a rate moves from 10% to 12%, it rose by 2 percentage points, but by 20 percent relative to its old value. Use the percent-change mode for the relative figure.
▸Can it handle decimals and negative numbers?
Yes. Percent change with negative starting values is handled by taking the absolute value of the base, which is the standard convention for growth-rate reporting.