Calculate percentages, percentage changes, and discounts with ease
Percentages appear in almost every area of daily life — shopping discounts, salary increases, tax calculations, exam scores, investment returns, and more. While the basic concept is simple (per hundred), the specific calculation you need varies depending on the question being asked.
The CalcNest Percentage Calculator handles all common types of percentage problems in one place: finding a percentage of a number, calculating percentage change between two values, finding what percentage one number is of another, and working backwards to find an original value before a percentage was applied.
Percentage change must always use the original (starting) value as the denominator — not the new value. 'Price dropped from £80 to £60' is a 25% decrease (20/80), not a 33% decrease (20/60).
A 20% increase followed by a 20% decrease does NOT return to the starting point. It results in a 4% net loss (1.20 × 0.80 = 0.96). Sequential percentage changes must be multiplied, not added.
If a price is £120 after a 20% increase, the original price is NOT £120 − 20% (= £96). The correct calculation is £120 ÷ 1.20 = £100. Always divide — never subtract the percentage from the new value.
If interest rates rise from 4% to 5%, that is 1 percentage point — but a 25% increase in the rate. These are fundamentally different measures and are frequently confused in media reporting.
Move the decimal point one place to the left. 10% of £340 = £34. 10% of £1,250 = £125. From there: 5% is half of 10%, 20% is double of 10%, 15% is 10% + 5%, and 1% is 10% ÷ 10.
A markup is profit as a percentage of cost. A profit margin is profit as a percentage of selling price. If an item costs £40 and sells for £50: the markup is (10/40)×100 = 25%, but the profit margin is (10/50)×100 = 20%. These are not interchangeable.
In the UK, standard VAT is 20%. To add VAT: multiply by 1.20. To remove VAT from a VAT-inclusive price: divide by 1.20. To find the VAT amount in a VAT-inclusive price: Price ÷ 6 (because 20/120 = 1/6).
Yes. A 200% increase means the value has tripled (original + 200% of original = 3× original). A value can also decrease by a maximum of 100% (to zero). An increase of more than 100% is perfectly valid mathematically.