Find part, share or whole
Use Find a percentage for a part of a number, Find what percent for a share of a total, or Find the whole when the percentage and part are known.
Everyday percentage maths
Percentage Calculator
Calculate percentages, changes, differences, percentage points and discounts. Choose the question first, then see the answer, formula and plain-English meaning.
What are you trying to figure out?
Step 1
Choose the question
Pick the calculation that matches your situation.
Step 2
Enter your values
The labels update to match the question you selected.
All calculations stay in this browser.
20% of 150
- In plain English
- 20% of 150
- Formula
- 150 × 20 / 100
How to use it
Match the calculation to the question you have.
Describe a change clearly
Use See a change when there is a before and after value. It reports both the absolute difference and the relative percentage change.
Compare rates and prices
Use Compare rates for percentage points, Compare two values when neither value is the baseline, and the discount options for sale prices.
Useful for
Quick answers for prices, reports and everyday comparisons.
Shopping and pricing
Check a discount, compare a price change, or find the original price before a sale.
Work and school
Turn a part into a percentage, compare two values, or explain a result with the displayed formula.
Rates and dashboards
Separate a percentage-point movement from a relative percentage change when reading conversion, interest or survey rates.
Method & limits
Standard percentage arithmetic, with the context shown.
Percentage of a number
The calculator multiplies the number by the percentage divided by 100.
Change and difference
Percentage change uses the starting value as its baseline. Percentage difference uses the average of two non-negative values.
Important limits
A percentage change from zero is undefined. Comparing signed values with percentage difference can be misleading, so the calculator explains these cases instead of hiding them.
FAQ
Percentage Calculator FAQ
What is the difference between percentage change and percentage points?
Percentage change measures the relative change from a starting value. Percentage points are the direct subtraction between two rates: a move from 2% to 3% is 1 percentage point, while the relative increase is 50%.
When should I use percentage difference?
Use percentage difference to compare two independent, non-negative values when neither one is the starting baseline. If one value happened before the other, Percentage Change is usually the clearer choice.
Why is percentage change undefined when the starting value is zero?
Percentage change divides by the starting value. Division by zero has no defined arithmetic result, so the calculator still shows the absolute change and explains the limit.
How do I calculate a discount or original price?
Choose Check a discount to subtract a percentage from a price. Choose Find original price when you know the sale price and discount rate and want the pre-discount amount.
Are my values sent anywhere?
No. The calculation runs in the current browser. ToolkitLoop does not send the values you enter to a calculator service.