Percentage Calculator
Calculate percent of a number, percent change, discounts, increases, decreases, and what percent one value is of another.
Try a common percentage task
Calculated result
30
15% of 200 = 30
Percentage math is a helper. Confirm final rounding, taxes, invoices, and spreadsheet formulas in the system that will use the number.
A percentage calculator solves questions like X% of Y, percent change, and what percent one number is of another.
For percent change, subtract old from new, divide by old, then multiply by 100.
Identify the base value
The base value is the whole, original price, old value, or denominator in the question.
Keep percent points separate
Moving from 10% to 15% is 5 percentage points, but a 50% relative increase.
X% of Y
Result = (X / 100) × Y
15% of 200 = 30
X is what percent of Y
Percent = (X / Y) × 100
30 of 200 = 15%
Percent change
Change = ((new - old) / old) × 100
120 to 150 = 25% increase
Add or subtract percentage
Final = value × (1 ± percent / 100)
200 minus 15% = 170
Example
A move from 10% to 15% is 5 percentage points, but it is a 50% relative increase.
Assumption
Percent change uses the old value as the base. Discount and markup modes apply one percentage at a time.
Limitation
Division by zero is invalid, and displayed values may be rounded. Financial rates may need more context.
Discounts
Calculate sale prices, savings, and percent-off values for shopping comparisons.
Growth rates
Find percentage increases or decreases between old and new values.
Shares of a total
Work out what percent one value represents out of a larger whole.
Markup and markdown
Add or subtract a percentage for pricing, planning, and quick estimates.
What is the fastest way to calculate 10%?
Move the decimal point one place left. For example, 10% of 250 is 25. You can then scale from there, such as 20% = 50 and 5% = 12.5.
What is the difference between percentage and percentage points?
A percentage is relative to a base value. Percentage points describe the absolute difference between two percentages. Moving from 10% to 15% is a 5 percentage point increase, but a 50% relative increase.
Can percent change be negative?
Yes. A negative percent change means the new value is lower than the old value. For example, 100 to 80 is a 20% decrease.
Does this tool use a server?
Percentage calculations are handled in the browser for this tool based on the current public implementation.
Suggested workflow
Everyday percentage math path
Use percentage math as a bridge between shopping, finance, and conversion workflows.