Percent Error Calculator

Percentage Calculator
Calculate percentages with different methods

What is X% of Y?

Calculate a percentage of a number

What this calculator does

The percentage calculator has modes for "What is X% of Y?", "X is what percent of Y?", and percentage change between two numbers. It is a general-purpose tool for everyday percentage calculations.

Use it for discounts, markups, test scores, growth rates, and any situation where you need to translate between actual values and percentages.

How to use this calculator

Enter your information in the fields above, run the calculation, and review the result to understand what it means for your situation.

How to interpret your result

Look at the output in the context of your overall goals rather than in isolation. Consider how sensitive the result is to changes in your inputs (for example, adjusting the amount, rate, or time) to understand which factors matter most.

Limitations and notes

This tool is a simplified model and does not capture every nuance of real life. Treat it as a planning aid, not a guarantee. For important financial or health decisions, combine these results with professional advice and more detailed analysis.