The Three Main Percentage Formulas
Percentages are used in everything from calculating tips and taxes to measuring stock market growth. This tool combines the three most common percentage calculations into one interface.
1. Finding a Percentage
Use the first row when you need to calculate a portion of a whole number (e.g., "What is 20% of 150?").
Result = (Percent ÷ 100) × Number
2. Finding What Percent One Number is of Another
Use the second row to determine the relationship between two numbers (e.g., "50 is what percent of 200?").
Result = (Part ÷ Whole) × 100
3. Percentage Change (Increase/Decrease)
Use the third row to find the growth or decline from an old value to a new value (e.g., "Change from $50 to $75"). If the result is positive, it's an increase. If negative, it's a decrease.
Result = ((New Value - Old Value) ÷ |Old Value|) × 100
Step-by-Step Instructions
- Identify which type of calculation you need (finding a value, finding a ratio, or finding a change).
- Enter your numbers into the corresponding row's input fields.
- The calculator updates instantly. For "Percent Change," a negative sign indicates a decrease in value.