How to Use a Percentage Calculator Online
Calculate percent of a number, percentage increase, percentage decrease, and percent share for everyday math and reports.
Open Percentage Calculator
Percentage questions appear in discounts, grades, reports, analytics, finance checks, and everyday comparisons. A percentage calculator helps answer several related questions without rewriting formulas each time.
Common percentage calculations
- Find 20 percent of 150.
- Calculate what percent one value is of another.
- Measure percentage increase from an old value to a new value.
- Measure percentage decrease for discounts, drops, and reductions.
How percentage change works
Percentage change compares the difference between two values to the original value. If a value moves from 80 to 100, the difference is 20 and the original value is 80, so the percentage increase is 25 percent.
Where percentages are useful
Percentages make different quantities easier to compare. A marketer may compare conversion rates, a student may calculate a grade, a shopper may check a discount, and a product team may track growth between two time periods.
FAQ
How do I calculate a percentage increase?
Subtract the old value from the new value, divide by the old value, then multiply by 100.
How do I calculate a percentage decrease?
Subtract the new value from the old value, divide by the old value, then multiply by 100.
What does percent of a number mean?
It means finding the portion represented by a percentage, such as 20 percent of 150 being 30.