Percentage calculator
Type two numbers and see the three most-used percentage calculations at once.
Free · no sign-up The values you type stay in your browser: nothing is sent or stored.
A% of B
30.00
- A is what % of B
- 13.3%
- Change from A to B
- 650.0%
Your result in words
20.00% of 150.00 is 30.00; 20.00 is 13.33% of 150.00; and from 20.00 to 150.00 the change is 650%.
Informational estimate, without fees or inflation. Check taxes and charges for your case; the real result may differ.
How it works
The three calculations
A percentage of a value (what is 20% of 150), what percent one number is of another (20 is what percent of 150) and percentage change (from 20 to 150, how much did it rise). The calculator does all three with the same two numbers.
Increase and discount
To apply an A% discount to B, use B minus A% of B. For an increase, B plus A% of B. A 50% drop followed by a 50% rise does not return to the starting value.
Formula
How to calculate
p is A% of B, q is what percent A is of B and Δ is the percentage change from A to B (negative when the value drops).
Example
With round numbers, so you can check the math:
20.00% of 150.00 is 30.00; 20.00 is 13.33% of 150.00; and from 20.00 to 150.00 the change is 650%.
Frequently asked questions
How do I find 10% of a value?
Type 10 in A and the value in B: the first result is 10% of B. It is the same as dividing B by 10.
How do I calculate a product discount?
Type the discount percentage in A and the price in B. Subtract the first result from the price to get the discounted amount.
Can the change be negative?
Yes. When B is smaller than A the change is negative and means a drop. When A is zero the change does not exist.
Math checked by the JuntaTudo team · updated on Nov 12, 2026
