Percentage Calculator
Work out percentages three different ways: what X% of a number is, what proportion one number is of another, and the percentage change between two values. They are the three questions that actually come up, kept on one page so you do not have to remember which formula goes with which.
A general-purpose calculation, not financial, tax or investment advice.
How to calculate a percentage
- Choose the type of percentage calculation you need.
- Type in your two numbers.
- Read the answer instantly — it updates as you type.
When you'd use this
- Discounts and tips — Finding 15% of a bill, or checking what a shop's advertised reduction really comes to.
- Marks and scores — Turning 47 out of 60 into a percentage for a report or an application.
- Price changes — Working out how much a rent, a fare or a subscription rose between two years.
- Targets and progress — Seeing what share of a goal has been reached so far.
Good to know
- Three modes, three questions — X% of Y finds a part of a whole. X is what % of Y turns a fraction into a percentage. % change compares a before and an after.
- Percentage change can be negative — A fall from 200 to 150 is −25%. The sign tells you the direction, so read it rather than ignoring it.
- Increases and decreases are not symmetrical — A 50% rise followed by a 50% fall does not bring you back to where you started — it leaves you 25% down.
- Results update as you type — There is no calculate button; change any figure and the answer follows immediately.
Frequently asked questions
Does this update automatically?
Yes — the result updates instantly as you type, no button to press.
Can I calculate a percentage increase or decrease?
Yes — use the “% change” tab and enter the starting and ending values.
How do I calculate a percentage increase?
Use the % change mode: enter the original figure as From and the new one as To. A rise shows as a positive percentage and a fall as a negative one.
How do I work out marks as a percentage?
Use the X is what % of Y mode — your score goes in the first box and the total in the second, so 47 and 60 gives 78.33%.
How do I remove a percentage from a price?
For a straightforward reduction, find the percentage with the first mode and subtract it. If you are stripping out tax that is already included in a price, the GST Calculator's remove mode does that properly.