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.