Percentage Calculator
This percentage calculator helps with common school and everyday math questions such as what percent one number is of another, what a given percentage of a number equals, and how much a value increased or decreased.
It works well for grades, discounts, test scores, and growth comparisons.
The layouts and outputs use plain U.S.
number formatting.
| Formula used | 18 is 90% of 20. | |
|---|---|---|
| Value X | 18 | |
| Value Y | 20 |
Assumptions
- Percentage change uses Value X as the original value and Value Y as the new value.
- Results can look extreme when the original value is near zero.
- This calculator uses plain arithmetic and does not handle school-specific grading curves.
How this calculator works
What it estimates
Solve percent of a number, part-over-whole, and percentage change problems.
Formula and example
- Common formulas include part / whole x 100 for percent, percent / 100 x number for percent of a value, and (new - original) / original x 100 for percentage change.
- If you score 18 out of 20, the calculator can show that 18 is 90% of 20 and help compare that result with a previous test score.
Percentage Calculator FAQ
Is this percentage calculator exact?
It is an estimate for U.S. planning only. Your actual percentage result can change based on school grading policies, lender disclosures, test scaling, fees, or other real-world details.
Who should use this percentage calculator?
Students, parents, and families can use it to compare scenarios, double-check classroom math, or plan for college and student loan decisions before using official school or lender tools.
Does this replace official records or advice?
No. Use your school transcript, official testing account, financial aid package, or lender statement for final decisions. These tools are educational planning calculators only.