Four handy percentage tools in one place
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What is X% of Y?
Our free percentage calculator brings together four of the most commonly needed percentage calculations in one simple, easy-to-use tool. Whether you're working out a discount in a sale, tracking a change in your savings, comparing two figures, or splitting a bill, you'll find the right calculation here — no registration needed and no ads blocking your results.
This is the most common percentage calculation. Enter a percentage and a number, and the calculator instantly shows you the result. For example, 20% of £150 is £30 — useful for working out VAT, discounts, tips, commission, or savings targets. The formula used is simply: Result = (Percentage ÷ 100) × Number.
The percentage change tool tells you by how much a value has risen or fallen between two points, expressed as a percentage. Enter your original value and your new value, and the calculator works out whether the change is an increase or a decrease and by what proportion. This is particularly useful for comparing prices over time, tracking weight loss or gain, monitoring investment returns, or analysing business metrics. The formula is: % Change = ((New − Original) ÷ Original) × 100. A positive result means an increase; a negative result means a decrease.
Percentage difference is slightly different from percentage change. Rather than treating one number as the starting point, it compares two values symmetrically — useful when neither value is the "original." It's commonly used in science, statistics, and data analysis to express how far apart two measurements are relative to their average. The formula is: % Difference = (|A − B| ÷ ((A + B) ÷ 2)) × 100.
This tool answers the question "what share of the total does this number represent?" For example, if you scored 68 out of 80 in a test, you can instantly see that's 85%. It's equally useful for working out what percentage of your monthly income goes on rent, how much of a budget has been spent, or what proportion of a group has a certain characteristic. The formula is simply: % = (X ÷ Y) × 100.
One of the most frequent sources of confusion is mixing up percentage change and percentage difference. If a price rises from £80 to £100, the percentage change is 25% — but if you then ask what percentage it drops back to £80, the answer is 20%, not 25%. This is because the starting point is different. Our calculator handles the maths automatically, so you never need to worry about which formula applies.
Another common mistake is confusing "percentage points" with "percentages." If an interest rate rises from 2% to 3%, that's an increase of 1 percentage point — but it's actually a 50% increase in the rate itself. Context always matters when interpreting percentage figures.
For simple cases, a few mental maths tricks work well. To find 10%, move the decimal point one place to the left. To find 5%, halve the 10% figure. To find 20%, double the 10% figure. For less round numbers, our calculator will always give you an accurate result instantly.
Yes. To add 20% VAT to a net price, use the "% of a number" tool and enter 20% of your net price, then add it to the original. To find the VAT-exclusive price from a VAT-inclusive price, use the "What % is X of Y?" tool to understand the proportions, or simply divide the gross price by 1.2.
No. Percentage change measures movement from a defined starting point to an end point and has a direction (increase or decrease). Percentage difference compares two values without assigning either as the reference point, and always produces a positive result. Use percentage change for tracking something over time, and percentage difference when comparing two independent measurements.
Results are for informational purposes only. Always verify important calculations independently.