Everyday percentage math
Percentage Calculator
Quick answer: This percentage calculator helps students, shoppers, and professionals solve common percent, ratio, and percentage change questions quickly.
Enter your details below and see your result instantly — no sign-up required.
Use this percentage calculator for the three most common percentage questions: what is a percent of a number, what percent one number is of another, and how much a value changed in percentage terms.
Explore this calculator further
3 ways to calculate percentages
Each mini-calculator updates live so you can test multiple scenarios without resetting the page.
What is X% of Y?
X is what % of Y?
Percentage change from X to Y
When to use each percentage formula
The first formula is useful when you already know the percentage and want the amount, like calculating a discount, tax, or commission. It answers questions like “What is 20% of 85?”
The second formula works when you know the part and the whole and want the relationship between them. It is common in grade breakdowns, budget categories, and conversion rates.
The third formula is for growth and decline. It helps compare before-and-after numbers, like price changes, sales performance, or weight changes over time.
Frequently Asked Questions
Divide the first number by the second number and multiply by 100. That gives the percentage relationship between the two values.
Subtract the starting value from the ending value, divide by the starting value, and multiply by 100.
Percentage change is negative when the ending value is lower than the starting value, which indicates a decrease.
Percentages make comparisons easier across prices, grades, discounts, growth, and part-to-whole relationships.