Calculators
Percentage Calculator
Calculate percentages, ratios, and percent change.
Core percentage questions
Increase / decrease a value
What is this tool?
Work out a discount, a tip, a grade, or a year-over-year growth figure without reaching for a spreadsheet. Enter two numbers and the calculator answers the three most common percentage questions at once.
Percentage problems show up in discounts, growth metrics, grades, and tip calculations. ToolForge computes the common variants in one place.
Percent change uses ((new − old) / |old|) × 100. Division by zero yields an unavailable result rather than crashing.
How to use the Percentage Calculator
- Enter the two values involved in your percentage question.
- Review results for “X% of Y”, “X is what % of Y”, and percent change.
- Optionally apply an increase or decrease percentage to a base value.
Examples
15% of 200
Result: 30
Frequently asked questions
How is percent change defined?
((new value − original value) / absolute value of original) × 100. If the original is zero, percent change is undefined.
How do I calculate a discount?
Enter the original price as the base value and the discount as the percentage, then apply a decrease. For example, 20% off 80 gives 64.
What is the difference between percent change and percentage points?
Going from 10% to 15% is a rise of 5 percentage points but a 50% percent change, because the increase is half of the starting value.
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