Percentage Calculator
Three quick percentage calculators in one — find what X% of a number is, what percentage one number is of another, or the percentage change between two values.
How to Use This Tool
Pick the right calculator
Three sections above cover the three most common percentage questions.
Enter your two numbers
Fill in the blanks in the sentence for your chosen calculator.
Click "Calculate"
Get an instant, precise answer.
Use the result
Apply it directly to pricing, discounts, growth analysis, or reporting.
About the Percentage Calculator
Percentage calculations come up constantly in everyday work — figuring out a discount, checking what portion of a budget was spent, calculating growth between two periods — but the three common variations of the question (finding a percentage of a number, finding what percentage one number is of another, and finding percentage change) each use a slightly different formula that's easy to mix up.
This tool separates the three most common percentage questions into their own clearly labeled calculators, so you pick the one matching your actual question rather than needing to remember which formula applies to which scenario.
Percentage change specifically (the third calculator) is useful for tracking growth or decline between two values over time — revenue this quarter versus last quarter, traffic this month versus last month — and correctly shows a negative percentage when the second number is lower than the first.
Frequently Asked Questions
What's the difference between "X% of Y" and "X is what % of Y"?
"What is X% of Y" starts with a known percentage and finds the resulting value (like finding 20% of 150 equals 30). "X is what % of Y" starts with two known values and finds the percentage relationship between them (like finding that 30 is 20% of 150) — they're inverse operations of each other.
How is percentage change calculated?
Percentage change is calculated as (New Value − Old Value) ÷ Old Value × 100. A positive result means an increase, and a negative result means a decrease from the old value to the new value.
Why does percentage change show a negative number sometimes?
A negative percentage change indicates the second (new) value is lower than the first (old) value — representing a decrease. For example, going from 100 to 80 shows a -20% change, correctly indicating a decline.
Can I use the percentage change calculator for things other than money, like website traffic?
Yes — percentage change works for any pair of comparable numeric values, whether that's revenue, website visitors, project hours, or any other metric you're comparing between two points in time or two categories.
Is there a difference between "percentage change" and "percentage points"?
Yes, and they're often confused — percentage change is a relative measure (e.g., going from 10% to 15% is a 50% relative increase), while a percentage point difference is a simple subtraction (going from 10% to 15% is a 5 percentage point increase). This calculator computes relative percentage change.
Are these calculations rounded, or exact?
The calculator shows results to two decimal places for precision, though very small or very large numbers may display with different rounding depending on the specific values entered.