Percentage Calculator
Four percentage modes in one place: percent of a number, what percent X is of Y, percent change, and add or subtract a percent. Results update as you type.
percentWhat is X% of Y?
helpX is what % of Y?
trending_up% Change from X to Y
calculateAdd/Subtract X% to Y
What is the Percentage Calculator?
A percentage calculator runs the four math operations that account for almost every percent question in real life: finding part of a whole, finding what fraction one number is of another, the change between two values, and adding or subtracting a percent (sales tax, tips, discounts). Doing them by hand is fine for round numbers and slow for everything else.
How to use the Percentage Calculator
- 1
Pick the right card
Each of the four cards answers a different shape of question. Find the one that matches what you actually need to know.
- 2
Type the two numbers
Both inputs accept decimals and negative numbers. The answer appears below the card the moment both fields have values.
- 3
Read the result
Percent change tiles also show direction (increase or decrease) and color the result green or red.
- 4
Copy or rerun
Tap into the same card with new numbers to recalculate. Each card holds its own state, so you can run several scenarios in parallel.
Frequently Asked Questions
What calculation modes are available?
Four. (1) What is X% of Y, for tips and discounts. (2) X is what % of Y, for grades and conversion rates. (3) Percent change between two numbers, for tracking growth. (4) Add or subtract a percent to a number, for tax, markup, or sale prices.
How is percentage change calculated?
((New - Old) / Old) × 100. So 50 to 75 is +50% (an increase), and 100 to 80 is -20% (a decrease). The card colors the result green for positive, red for negative.
Can I calculate tips?
Two ways. Card 1: "What is 15% of 50?" gives the tip amount (7.50). Card 4: "50 + 15%" gives the total bill including tip (57.50). Pick whichever matches what you actually want to know.