🧮 Calculator Tools

Percentage Calculator

The three percentage questions you actually ask — answered instantly, right in your browser.

What is% of?
= 30
Overview

Percentage Calculator: the three percent questions, solved instantly

Percentages come up constantly — a discount in a sale, a tip at a restaurant, a tax rate, a test score, a price change between two months. This calculator covers the three questions that account for almost every real percentage problem: what is X% of a number, what percent one number is of another, and the percentage increase or decrease between two values. Pick a mode, type your numbers, and the answer appears as you type.

Everything is computed locally in your browser, so it works offline once the page loads and nothing you enter is sent anywhere. It is built to be faster than reaching for a phone calculator and remembering which way the formula goes.

100% freeNo sign-upRuns in your browserThree calculation modes
How to use it
  1. 1Choose the mode that matches your question: '% of a number', 'X is what % of Y', or '% increase / decrease'.
  2. 2Type your two numbers into the sentence — the result updates instantly, no button needed.
  3. 3For percentage change, a green ▲ means an increase and a red ▼ means a decrease.
  4. 4Switch modes anytime; each keeps its own values so you can compare quickly.
Key features
  • Find X% of any number (discounts, tips, tax, commissions)
  • Work out what percent one value is of another (scores, shares)
  • Calculate percentage increase or decrease between two values
  • Live results that update as you type — no submit button
  • Clear increase/decrease direction with color and arrows
  • 100% client-side — your numbers never leave your device

Frequently asked questions

How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 15% of 200 is 200 × 15 ÷ 100 = 30. The '% of a number' mode does this for you.
How is percentage change calculated?
Subtract the old value from the new value, divide by the old value, and multiply by 100. A result above zero is an increase; below zero is a decrease.
What is the difference between percent and percentage points?
A percentage is a proportion of a value; percentage points are the simple arithmetic difference between two percentages. Going from 10% to 12% is a 2 percentage-point rise but a 20% increase.
Is the calculator free?
Yes — completely free, no sign-up, and it runs entirely in your browser.
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Full guide

Percentages Made Simple — Complete Guide

Learn how to calculate percentages, percentage change, and avoid the common percent vs. percentage-points mistake.

Percent of a numberPercentage increase & decreasePercent vs. percentage points

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