How to use Percentage Calculator
- Choose the type of percentage problem.
- Enter the known values.
- Read the calculated percentage or amount.
Worked examples
Concrete numbers and cases you can check against the tool above.
18% of a $86 restaurant bill
0.18 × 86 = $15.48 tip; total $101.48. “86 is what percent of 200?” is 86/200 = 43%. Percent change from 80 to 100 is (100−80)/80 = 25% increase, not 20%. Those three problem types are easy to mix up; pick the matching mode.
When to use Percentage Calculator
Discounts, tips, exam scores, and growth rates are percentage problems in disguise. A dedicated calculator removes algebra mistakes under time pressure and keeps homework or business figures offline. Whether you need “what is X% of Y” or percent change between two values, the same tool covers everyday cases.
Common use cases
- Find what 18% tip is on a restaurant bill before paying.
- Compute percent change between two months of revenue.
- Solve “X is what percent of Y” homework quickly and clearly.
- Reverse out an original price after a markdown to check the deal.
Inputs and outputs
- Numeric values and percents
Privacy
This tool runs entirely in your browser. Your data never leaves your device — nothing is uploaded to our servers.
Frequently asked questions
- How do I calculate percent increase?
- Subtract the old value from the new, divide by the old value, and multiply by 100. The tool does this when you use the increase/decrease mode.
- Can it do reverse percentages?
- Yes for common cases like finding the original amount before a percent was applied, when that mode is selected.
- Are inputs saved?
- No.