Percent vs percentage points
Moving from 20% to 25% is 5 percentage points, but the relative increase is 25% because 5 is one quarter of 20.
Percentage Calculator
Plain-English percentage calculator
Percentage calculator for everyday questions.
What is a percentage of a number?
Use this when you need a portion of a number, such as 20% of 80.
What is 20% of 100?
About this percentage
EverydayUse this for discounts, tips, fees, marks, targets and any question where one number is part of another.
A percentage is a number out of 100. For example, 20% means 20 out of every 100.
Recent results
Useful notes
GlossaryHow to use the percentage calculator
Start by choosing the type of percentage question that matches what you are trying to answer. For example, use "What is 20% of a number?" when you know the percentage and the original number, use "What percent is this?" when you are comparing one value with another, and use the discount or markup modes when you want to understand a sale price or price increase.
The calculator updates the answer as you type. The answer card gives the final value, while the visible steps show the arithmetic in plain language. This is useful when you want to check a shop discount, explain a fee, compare two figures, or copy the method into a note or message.
Limitations
This is an estimate-only percentage maths tool for general guidance. It can help with shopping, school marks, fees, estimates and simple comparisons, but it does not decide tax treatment, investment returns, borrowing affordability or legal obligations. Check the relevant source where a decision depends on the result.
Percentage examples
Common checks| Question | Working | Answer |
|---|---|---|
| What is 20% of 100? | 100 x 0.20 | 20 |
| What percent is 30 of 120? | 30 / 120 x 100 | 25% |
| 25% off GBP 80 | 80 - (80 x 0.25) | GBP 60 |
| Increase from 80 to 100 | (100 - 80) / 80 x 100 | 25% increase from the starting value of 80 |
| Decrease from 100 to 80 | (100 - 80) / 100 x 100 | 20% decrease from the starting value of 100 |
These two percentage-change examples use different starting values. The increase compares 20 with 80, while the decrease compares 20 with 100.
Common percentage mistakes
Sense-checksIncrease and decrease are not symmetric
A 25% increase from 80 gives 100. A fall from 100 back to 80 is a 20% decrease because the starting value changed.
Reverse discounts need the sale-price share
If GBP 75 is the price after 25% off, it represents 75% of the original price. Divide 75 by 0.75 to estimate GBP 100.
Percentage calculator FAQs
What can this percentage calculator work out?
It can work out percentage of a number, what percent one number is of another, percentage change, discounts, VAT, markups, margins, reverse discounts, ratios, percentage points and percent difference.
How do I calculate percentage change?
Enter the starting value and the new value. The calculator finds the difference, divides it by the starting value, and turns that into a percentage.
Can it add or remove VAT?
Yes. Use Add VAT when you have a price before tax, or Remove VAT when the price already includes VAT. Use the VAT calculator when you want net, VAT and gross amounts separated clearly.
Does the calculator show its working?
Yes. Each mode shows the answer plus clear steps explaining how the result was calculated.
Is a percentage point the same as a percent change?
No. A move from 20% to 25% is 5 percentage points, but it is a 25% relative increase compared with the starting 20%.