Percentage Calculator
A complete percentage calculator with four modes: what is X% of a value, what percent one number is of another, the percent change between two numbers (increase or decrease), and increasing or decreasing a value by a percent. Useful for discounts, raises, VAT, and commissions.
How to Use
- Pick the mode you need from the four tabs
- Enter the two values — the field labels change with the mode
- The result appears instantly; the change mode also shows whether it is an increase or a decrease
- Copy the link to share the calculation with the same values
A Four-Mode Percentage Calculator
A percentage expresses a part per hundred. This calculator bundles the four most common percentage calculations into one tool so you never have to recall the formulas.
1. What is X% of a value?
To take a percent of an amount, multiply the amount by the percent divided by 100. Example: 15% of 200 = (15 ÷ 100) × 200 = 30. Handy for VAT, commission, or a discount amount.
2. What percent is one value of another?
To find what percent one number is of another, divide the part by the whole and multiply by 100. Example: 30 of 150 = (30 ÷ 150) × 100 = 20%.
3. Percent change
To measure the increase or decrease between two numbers, subtract the original from the new value, divide by the original, then multiply by 100. A positive sign means an increase, a negative sign a decrease.
4. Increase or decrease a value by a percent
To add or subtract a percent from a value, multiply it by (1 + percent ÷ 100). A negative percent decreases the value. Useful for a price after a rise or a salary after a raise.
Calculation Methodology
The formulas used
Percent of a value: (X ÷ 100) × Y. What percent of another: (part ÷ whole) × 100. Percent change: ((new − original) ÷ |original|) × 100. Adjust by a percent: value × (1 + percent ÷ 100).
Negative values and division by zero
Negative values are accepted (a decrease, or a negative base). In the "what percent" and "percent change" modes, dividing by zero is undefined, so a warning is shown instead of an incorrect result. The change mode uses the absolute value of the base so the sign reflects an increase or a decrease.
Practical Examples
The tax on an invoice
Khalid wanted the VAT on a 200 SAR amount at 15%. 15% of 200 = 30 SAR. He used the "percent of a value" mode.
Completion rate
Salma finished 30 of 150 tasks. (30 ÷ 150) × 100 = 20% of the work is done. She used the "what percent" mode.
A price increase
A product rose from 80 to 100 SAR. Percent change = ((100 − 80) ÷ 80) × 100 = +25% increase. The "percent change" mode marks it as an increase.
Frequently Asked Questions
How do I calculate a percentage of an amount?
What is the difference between percent increase and percent of a value?
How do I calculate the percent change between two numbers?
Does the calculator support negative values?
Disclaimer: The results shown are approximate and for reference only, and do not constitute financial or legal advice. Actual amounts may vary based on additional factors. Please consult the relevant official authorities or a licensed financial advisor for accurate information specific to your situation.