About This Percentage Calculator

This free percentage calculator combines three of the most commonly needed percentage calculations into one simple tool. Whether you need to find a percentage of a number, work out what percentage one value is of another, or calculate how much something has increased or decreased, you can switch between modes instantly without leaving the page.

The first mode answers the question most people search for: what is X percent of a number? This is useful for calculating tips, discounts, tax amounts, commission, interest, and anything else where you need to find a fraction of a total. Simply enter the percentage and the number, and the result appears instantly.

The second mode works in reverse: given two numbers, it tells you what percentage the first is of the second. This is helpful for calculating test scores, budget percentages, market share, nutritional breakdowns, and any situation where you need to express one quantity as a proportion of another.

The third mode calculates percentage change between two values. It tells you whether the change is an increase or a decrease, and by exactly how much. This is widely used for comparing prices, tracking investment returns, measuring growth rates, and analysing any metric that changes over time.

Frequently Asked Questions

To find X percent of a number, multiply the number by the percentage and divide by 100. For example, 20% of 150 is calculated as 150 multiplied by 20, divided by 100, which equals 30. Alternatively, convert the percentage to a decimal by dividing by 100 (20% becomes 0.20), then multiply by the number (0.20 times 150 equals 30).

Divide the part by the whole, then multiply by 100. For example, to find what percentage 30 is of 150, divide 30 by 150 to get 0.2, then multiply by 100 to get 20%. This formula works for any two numbers, including decimals and fractions.

Percentage change is calculated by subtracting the original value from the new value, dividing the result by the original value, then multiplying by 100. For example, if a price goes from 80 to 100, the change is 20, divided by 80 equals 0.25, multiplied by 100 equals 25% increase. If the new value is lower than the original, the result is a negative number, indicating a percentage decrease.

Percentage change is the broader term that covers both increases and decreases. A percentage increase is a positive percentage change, meaning the new value is higher than the original. A percentage decrease is a negative percentage change, meaning the new value is lower. This calculator automatically determines whether the change is an increase or decrease and labels it accordingly.

Use the first mode, “What is X% of Y?” For a tip, enter the tip percentage (for example, 18) and the bill total. For a discount, enter the discount percentage and the original price to find the amount saved. To find the final price after a discount, subtract the result from the original price, or use our dedicated Tip Calculator and Discount Calculator for a more detailed breakdown.

Yes, the percentage calculator works for simple tax calculations such as adding GST, VAT or sales tax to a price. Enter the tax rate percentage and the pre-tax price in the first mode to find the tax amount, then add it to the original price. For more detailed tax calculations including province-by-province Canadian sales tax or country-by-country VAT, use our dedicated GST/HST/VAT Calculator.