Percentages appear everywhere — discounts, growth rates, exam scores, and financial metrics. This calculator handles the most common percentage questions in one place so you can verify results quickly.
How to use this calculator
- Select the type of percentage calculation you need.
- Enter Value A — for “percent of,” this is the percentage; for “what percent,” this is the part; for increase/decrease, this is the starting value; for change, this is the original value.
- Enter Value B — the base, whole, percent change amount, or new value depending on the mode.
- Review the result, explanation, and chart comparison.
Formula
Percent of: Result = (Percent ÷ 100) × Base. What percent: Result = (Part ÷ Whole) × 100. Increase: Result = Original × (1 + Percent ÷ 100). Decrease: Result = Original × (1 − Percent ÷ 100). Change: Result = ((New − Original) ÷ Original) × 100.
Example
25% of 200 equals 50. An increase from 80 to 100 is a 25% change. 30 is 15% of 200.
Frequently asked questions
What is the difference between markup and margin?
Markup is profit divided by cost. Margin is profit divided by selling price. They use different denominators and are not interchangeable.
Can I add two percentages together?
Only when they apply to the same base. Sequential percentage changes must be multiplied, not added — a 10% increase followed by another 10% increase is not a 20% total increase.
Why does percentage change show a negative result?
When the new value is lower than the original, percentage change is negative, indicating a decrease.
How do I find what percent one number is of another?
Select “X is what % of Y?” and enter the part as Value A and the whole as Value B. The result is (Part ÷ Whole) × 100.