Percentage Calculator
Use this free percentage calculator for X% of Y, percent change, increases, decreases, discounts, marks, tax, and quick comparisons online.
Browser-only processing
20% of 150 = 30.00
Related tools
More browser-based tools for this workflow.
What this tool does
Calculate percentages: X% of Y, what % is X of Y, percentage increase or decrease.
Use the three calculation modes to find X percent of Y, determine what percentage one value is of another, or measure the percent change between two numbers. Results update immediately as the inputs change.
Key features
- Find X% of Y for discounts, tax, marks, commissions, and tips
- Calculate what percent one number is of another for ratios and comparisons
- Measure percentage increase or decrease between an original and new value
- Instant recalculation makes it easy to compare several scenarios
- Responsive controls work in a phone, tablet, or desktop browser
Common use cases
- Checking a sale discount or the percentage portion of an invoice
- Comparing old and new prices, revenue, costs, or investment values
- Converting a score into a percentage for marks and assessments
- Measuring profit, loss, tax, or budget changes before moving figures into a spreadsheet
Things to know
- A zero original value has no conventional percentage-change result, so the tool returns zero
- Results follow standard arithmetic and may not include domain-specific rounding, fees, or tax rules
- For financial or legal decisions, verify the inputs and any rules that apply to your situation
Privacy & local processing
All percentage calculations run in your browser. The numbers you enter are not sent to WebToolsLabs or saved to an account.How to use Percentage Calculator
- 01
Choose X% of Y, X is what % of Y, or percentage change.
- 02
Enter the two numbers for your calculation.
- 03
Read the result instantly and adjust either value to compare another scenario.
Frequently asked questions
What can I calculate with this percentage calculator?
You can find X% of Y, determine what percent one number is of another, and calculate percentage change.
How do I calculate X percent of Y?
Choose X% of Y, enter the percentage as X and the base number as Y, and the result appears immediately.
Can I calculate percentage increase and decrease?
Yes. Percentage change shows a positive result for an increase and a negative result for a decrease.
Can I calculate what percent one number is of another?
Yes. Choose X is what % of Y and enter both values.
Is this calculator free?
Yes. It is free, browser-based, and requires no signup.