Percentage Calculator
Solve various percentage-based math problems quickly.
Loading Smart Logic...
Quick Tip
Choose the calculation you need: X% of Y, or percentage change.
About This Tool
Why use Percentage Calculator?
Two of the most common percentage questions in one place: what is X% of Y, and what is the percentage change from one number to another. The first multiplies — 25% of 400 is 100. The second divides the difference by the original value: from 80 to 100 is a 25% increase.
The direction of a percentage change matters. Going from 100 to 80 is a 20% decrease, but going back from 80 to 100 is a 25% increase, because each is measured against a different starting number. That asymmetry is behind most mistakes with discounts, markups and reported growth.
Key Benefits
Two calculations, one page
Taking a percentage and measuring a change cover most everyday percentage questions.
Direction handled correctly
Change is always measured against the original value, which is where manual calculations go wrong.
Instant results
No submit step — type the numbers and the answer is there.
How to use Percentage Calculator
- 1
Choose the calculation you need: X% of Y, or percentage change.
- 2
Enter the two numbers.
- 3
Read the result, which updates as you type.
- 4
For percentage change, keep the original value in the first field so the direction is right.
Best use cases
Work out a tip, a discount or a commission.
Convert a score into a percentage.
Measure growth between two periods.
Check a percentage quoted in a report or an offer.
Percentage Calculator FAQs
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply. 15% of 240 is 0.15 × 240 = 36.
How do I work out percentage change?
(new − old) ÷ old × 100. From 50 to 65: 15 ÷ 50 × 100 = 30% increase.
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100. 45 out of 60 is 45 ÷ 60 × 100 = 75%.
What is the difference between percentage and percentage points?
A move from 10% to 12% is 2 percentage points, but a 20% increase. Reports use the two interchangeably far too often, which is a common source of confusion.
Related Finance Tools
More free finance tools that work well alongside percentage calculator.