Percentage Calculator
Calculate percentages, percentage increase/decrease, and what percent one number is of another.
About the Percentage Calculator
A percentage calculator solves the three most common percentage problems: finding what a percentage of a number is (what is 15% of 200?), finding what percent one number is of another (40 is what percent of 160?), and finding the percentage change between two numbers (increase or decrease). Instead of rearranging the percentage formula by hand, you enter the numbers you know and the tool fills in the rest.
It's built for everyday situations — working out a restaurant tip, a discount at checkout, a grade on a test, or how much a salary or investment has grown or shrunk over time — where speed and accuracy matter more than showing your work.
Worked example
Example: a $80 jacket is on sale for $60. Using the percentage-decrease mode, enter 80 as the original value and 60 as the new value — the tool returns a 25% decrease, which is the discount rate applied at checkout.
Frequently asked questions
- How do I calculate a percentage increase?
- Subtract the original value from the new value, divide by the original value, then multiply by 100. The percentage-increase mode of this calculator does this automatically — just enter the original and new numbers.
- What is the formula for 'X is what percent of Y'?
- Divide X by Y and multiply by 100: (X ÷ Y) × 100. For example, 40 is what percent of 160? (40 ÷ 160) × 100 = 25%.
- Can this calculator handle negative percentage changes?
- Yes. If the new value is smaller than the original, the increase/decrease mode returns a negative percentage, clearly indicating a decrease.
- Is a percentage the same as a percentage point?
- No — a percentage change is relative (e.g., a rate going from 10% to 15% is a 50% relative increase), while a percentage point change is absolute (a 5-point increase). This tool calculates relative percentage change.