Percentage Calculator
Percentages, increases, decreases, and shares — solved.
Runs 100% in your browser — nothing is uploaded
A fast, all-in-one percentage calculator: find X% of a number, work out what percentage one number is of another, calculate percentage increase or decrease, and add or subtract a percentage. Clear, step-by-step answers, right in your browser.
How to use percentage calculator
- Open the tool and provide the text, number, date, or file it asks for.
- Choose the format, mode, or settings that match the result you need.
- Review the result in the preview or output area.
- Copy the answer or download the finished file when it looks right.
Choose the percentage formula that matches the question
Percentage questions look similar but use different reference values. Use percentage of a number for a share, part divided by whole for a proportion, percentage change for an original and new value, and add or subtract a percentage for tax, tips, markups, or discounts. Selecting the correct mode is more important than memorising one universal formula.
For percentage change, the denominator is the original value. For percentage difference, the denominator is the average of the two values. This is why a move from 100 to 150 is a 50% increase, while moving from 150 back to 100 is a 33.33% decrease. Keep the original and new values labelled so the result can be explained to someone else.
Worked example: Example: 18% of 250 is (18 / 100) × 250 = 45; a 20% discount on 80 is 80 × (1 - 0.20) = 64.
Frequently asked questions
What can this calculator do?
Four common jobs: X% of a number, 'A is what percent of B', percentage increase/decrease between two numbers, and adding or subtracting a percentage from a value.
Does it show how the answer is worked out?
Yes. Each mode shows the formula and the numbers plugged in, so you can check the result and learn the method.
Is it good for discounts and tips?
Absolutely — use 'add/subtract a percentage' for tax, tips, and markups, and the increase/decrease mode for sale prices and changes over time.
Is anything uploaded?
No. All the maths runs locally in your browser; nothing is sent anywhere.
Related tools
Handy companions people often use alongside Percentage Calculator.