Percentage Calculator
Find percentages, compare changes and calculate discounts with instant, clear results.
X% of Y
Your values stay in your browser.
20% of 500 is 100.
Formula
Percentage ÷ 100 × value
Everyday percentage calculations
A percentage expresses a quantity per hundred. Use X% of Y to find a portion, or X is what % of Y to express a part relative to a whole. For example, 20% of 500 is 100, and 50 out of 200 is 25%.
Percentage change versus percentage difference
Increase and decrease compare a new value with an original value, using the magnitude of the original as the baseline. Results retain their sign: positive means an increase, negative means a decrease. Symmetric percentage difference uses the average magnitude of both values instead and has no directional baseline. Two zeros have a difference of 0%; change from a zero baseline is undefined.
Exam percentages and discounts
Exam percentage divides marks obtained by total marks and multiplies by 100, without assuming a grading system. Discount subtracts the discounted portion from the original price and shows the amount saved. Add and subtract modes apply a percentage of the original value; successive percentage changes are not simply added together.
Precision and privacy
Calculations use browser numeric precision without rounding intermediate values for display. Results show up to six decimal places, with scientific notation for very small or large values. Values beyond the numeric range produce a clear error. Your inputs and results are never sent to analytics.
How to use
- Choose the percentage task you need.
- Replace the two example values. The result updates instantly.
- Review the explanation and optional formula, or use Reset to restore the example.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 20 ÷ 100 × 500 = 100.
How do I calculate percentage increase or decrease?
Subtract the original value from the new value, divide by the absolute original value and multiply by 100. The sign shows the direction of the change.
What is percentage difference?
It is |A − B| divided by the average of |A| and |B|, multiplied by 100. This symmetric comparison does not depend on which value comes first.
Can I calculate exam percentage?
Yes. Enter marks obtained and the positive total marks. The tool shows the percentage without assigning a grade.
How do I calculate a discounted price?
Multiply the original price by one minus the discount percentage divided by 100. A ₹1,000 price with a 20% discount becomes ₹800, saving ₹200.
Are negative numbers supported?
General percentage modes support finite negative numbers. Exam marks and prices must be non-negative; discounts must be between 0% and 100%.
What happens when a denominator is zero?
Part-of-whole and percentage change show a validation message. The symmetric difference between two zeros is explicitly defined here as 0%.
Are my values uploaded?
No. Calculations run locally. Analytics can record the selected calculation mode after an edited, valid interaction, but never your inputs or results.