How to use this percentage calculator
Enter the values requested in the fields above. The result updates instantly as you make changes, so you can compare scenarios without reloading the page. Use decimal values where appropriate and review the unit or calculation mode before interpreting the answer.
How the calculation works
A percentage expresses a quantity as parts per hundred. Converting a comparison into a percentage makes values with different scales easier to understand—for example, a $15 discount on a $75 item is the same proportional saving as a $30 discount on a $150 item.
Percentage change compares a new value with an original value. The original value is the reference, so reversing the two inputs changes the answer. Percentage difference is different: it compares two values symmetrically by using their average as the reference.
Formulas
Percentage of a number
Percentage increase or decrease
Percentage difference
Worked examples
Find 18% of $240
(18 ÷ 100) × 240 = 43.2, so 18% of $240 is $43.20.
Measure a price increase
A price rises from $80 to $92. ((92 − 80) ÷ 80) × 100 = 15%, so the increase is 15%.
Common uses
Shopping and discounts
Work out the dollar value of a sale, compare two promotions, or check the final amount after a percentage discount. Calculate tax and fees separately when they use a different base.
Growth and performance
Measure changes in revenue, traffic, grades, budgets, or other tracked values. Use percentage change when one value is the starting point and percentage difference when neither value is the baseline.
Planning and comparison
Turn parts into shares of a total, test what-if scenarios, and communicate proportions on a common hundred-point scale. Keep the original value visible so readers can understand what the percentage describes.
Accuracy and limitations
The arithmetic follows the formulas shown above and retains full floating-point precision until the result is displayed. Small display differences can occur when a repeating decimal must be rounded.
A percentage is only as meaningful as its baseline. Confirm whether the question calls for percentage of a total, percentage change, or symmetric percentage difference before relying on the result.
Frequently asked questions
What is the difference between percentage change and percentage difference?
Percentage change uses the original value as its baseline and describes movement over time. Percentage difference uses the average of both values and is appropriate when neither value is the baseline.
Can a percentage increase be over 100%?
Yes. A value that more than doubles has increased by over 100%. For example, moving from 40 to 100 is a 150% increase.
Is the percentage calculator free to use?
Yes. NumUtility is free, requires no account, and places no limit on ordinary calculations.
Are my entries stored?
No. The calculation runs in your browser. Values entered into the tool are not sent to NumUtility or saved by us.