Percentage Calculator
Three handy percentage modes — pick one and calculate instantly.
What Is a Percentage Calculator?
A percentage calculator is a tool that solves everyday percentage problems without you having to remember or rearrange a formula each time. Percentages describe a part of a whole out of one hundred, and they turn up constantly in prices, scores, bills, and comparisons. The difficulty is rarely the idea itself, but choosing the right calculation for the question you are actually asking.
This calculator covers the three questions people ask most often. It can find what a given percentage of a number is, work out what percentage one number is of another, and measure the percentage increase or decrease between an old value and a new one. Each mode uses its own simple inputs, so you only enter the two numbers relevant to your question and get a clear answer straight away.
How to Use This Percentage Calculator
- Pick a mode from the Mode dropdown: What is X% of Y, X is what % of Y, or % increase / decrease from A to B.
- Enter your two numbers in the fields shown for that mode, following the examples in the placeholders if you are unsure which number goes where.
- Click Calculate and read the result in the blue box below.
- To try a different type of question, change the mode at the top. The previous result clears so you can start fresh.
Who Uses a Percentage Calculator?
Shoppers use one to check discounts and sale prices, students and teachers use one for marks and grades, and anyone reviewing bills, pay, or savings uses one to understand changes over time. Small business owners, freelancers, and people comparing prices or preparing simple reports also rely on percentage calculations regularly, especially when a quick, accurate answer matters more than working a formula out on paper.
Tips for Better Percentage Calculations
- Match the mode to your question. Finding a percentage of a number and finding what percentage one number is of another are different calculations, and picking the wrong one is the most common mistake.
- Take care with increase and decrease questions. Always enter the original value as the old value, because the percentage change is measured against where you started.
- Sanity-check the result. A discount should leave a smaller final amount, and a figure above one hundred percent means the part is larger than the whole you compared it with.
Frequently Asked Questions
Is this percentage calculator free to use?
Yes. It is free with no signup required, and the calculations happen in your browser on this page. The numbers you enter are not sent to a server or stored.
How do I work out a discount price?
Use the first mode to find the percentage of the original price, for example 20% of the price, then subtract that amount from the original price to get the sale price.
Why can a percentage be more than 100%?
A percentage compares one number with another. If the first number is larger than the number it is compared with, the result will be over 100%, which is normal for growth and comparison questions.
What is the difference between an increase in percent and the difference between two numbers?
The plain difference is simply the new value minus the old value. The percentage increase or decrease expresses that difference relative to the old value, which makes changes of different sizes easier to compare.