About this tool
Calculates percentages in three common modes: find X% of a value, find what percentage one number is of another, and calculate the percentage change between two values. Useful for discounts, tax, tips, interest, comparisons, and any everyday calculation involving percentages.
How to use
- Pick the calculation type: percentage of a value, part of total, or change.
- Fill in the two known values.
- The result updates in real time as you type.
Frequently asked questions
- How do you calculate a percentage of a value?
- Multiply the value by the percentage divided by 100. For example, 20% of 150 is 150 × 0.20 = 30. The tool does this automatically, just enter the two numbers.
- How do you calculate a percentage change?
- Subtract the starting value from the final, divide by the starting value, and multiply by 100. Positive change means increase, negative means decrease. Useful for tracking price, weight, audience, or any metric over time.
- Can I use negative numbers or decimals?
- Yes, both. Decimals are accepted with either a dot or a comma. Negatives work, but watch out for unusual cases: the percentage change between two values of opposite signs can give counter-intuitive results.