Percentage calculator
Find a percent of a number or apply a percent increase or decrease—useful for tips, simple discounts, and quick “what if” checks. Calculations run in your browser; we do not see your numbers.
How each mode works
- Percent of: Computes P% of the base:
(base × P) ÷ 100(e.g. 15% of 200 = 30). - Increase: Grows the base by P%:
base × (1 + P/100). - Decrease: Reduces the base by P%:
base × (1 − P/100)(e.g. a 25% discount on 80 = 60).
When a raw percentage can mislead
Percentages are only as good as the base and definition behind them. “10% more revenue” and “10% of revenue” are different ideas. In finance, headline rates may exclude fees; for health, “relative risk” can look large when the absolute risk is still small. Use this tool for transparent arithmetic, then double-check the real question you are trying to answer.
Everyday uses
- Estimating a restaurant tip or split-check share.
- Rough sale price from a “% off” tag on the original price.
- Quick compounding or markup checks before moving to a dedicated interest or business calculator.
Frequently asked questions
What does the “percent of” mode calculate?
It is P% of the base you entered, not the other way around.
Is this tax or financial advice?
No. It is a math helper. Use official tax tables, loan documents, and professionals for decisions that matter.
Disclaimer: For planning with fees, compounding, or tax rules, use a dedicated tool or professional advice. See accuracy and limitations.