Percentage Calculator

Calculate percentages, percentage change, and increase or decrease between two numbers instantly, free and accurate.

Overview

What is a percentage calculator?

A percentage calculator works out what portion one number represents of another, or how much a value has changed relative to a starting point, expressed as a percentage. It replaces manual arithmetic with an instant, accurate result for either type of calculation.

Percentages show up constantly in everyday and professional contexts — comparing prices, tracking growth, splitting bills, or analyzing data. Having a single tool that handles both "percentage of" and "percentage change" calculations removes the guesswork about which formula to apply by hand.

Guide

How to use it

Three steps, no learning curve — choose a type, enter numbers, read the result.

Step 01

Pick a calculation type

Choose whether you want to find a percentage of a number, or the percentage change between two numbers.

Step 02

Enter your numbers

Type the two values relevant to your chosen calculation into the input fields.

Step 03

Read the result instantly

The percentage result updates live as you type — no button to click.

Tips

Best practices to keep in mind

A few things worth knowing before trusting a percentage result.

Be clear on which base number you're measuring against — 'what percent of 80 is 20' and 'what percent did 80 change to 20' give very different results using the same two numbers.
Percentage change is directional. A 50% increase followed by a 50% decrease does not return you to the original number — the base amount changes between the two calculations.
When comparing percentage changes across different base values, remember that a 10% increase on a large number represents far more absolute change than 10% on a small one.
For discounts, tips, or tax specifically, a dedicated calculator that shows the final amount alongside the percentage can save a manual subtraction step — try the Discount Calculator for that.

Comparison

SEOJuicer vs. other percentage calculators

The same result, minus the uploads, the signup wall, and the paywall.

SEOJuicer

Runs entirely in your browser

Free, no signup required

Handles multiple calculation types

Live results as you type

Unlimited calculations

Other tools

Often loaded with ads

May require an account

Usually just one formula

Requires clicking calculate

Slower, server-based results

FAQs

Frequently asked questions

Have questions about calculating percentages? Here are the most common ones our users ask before getting started.

Is this percentage calculator free to use?

Yes, the percentage calculator is completely free with no signup, no usage limits, and no hidden charges. It runs entirely in your browser using JavaScript, so no data is sent anywhere and no account is ever required to work out a percentage.

What's the difference between percentage and percentage change?

Percentage of a number tells you what portion one value represents of another — for example, 20 is 25% of 80. Percentage change instead measures how much a value has grown or shrunk relative to its starting point — going from 80 to 20 is a 75% decrease. They use different formulas and answer different questions, so it matters which one you actually need.

How is percentage change calculated?

Percentage change is calculated by subtracting the original value from the new value, dividing that difference by the original value, and multiplying by 100. A positive result means an increase and a negative result means a decrease, which this calculator shows automatically based on the two numbers you enter.

Can I calculate a percentage increase or decrease with this tool?

Yes — enter your starting value and your new value, and the calculator works out both the direction and the exact percentage change between them. This is useful for tracking things like price changes, growth in a metric over time, or the difference between two measurements.

Does this tool store or share the numbers I enter?

No. The entire calculation happens locally in your browser — the numbers you enter are never transmitted to a server, logged, or stored anywhere. You can run as many percentage calculations as you need without any of that data being retained.

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