Percentage Calculator — Find %, Increase, Decrease & Difference
A flexible percentage calculator that handles the four most common percent problems instantly.
About this calculator
Percentage calculations come up everywhere — discounts on Shopee Sale, your SST line on a restaurant bill, your annual salary increment, the growth of your investment, the score on a midterm exam. The four most common forms are: (1) X% of Y → simply (X/100) × Y; (2) X is what % of Y → (X/Y) × 100; (3) percentage change from A to B → ((B − A) / A) × 100; (4) percentage difference between two values → |A − B| / ((A + B) / 2) × 100. The difference between 'change' and 'difference' matters and is the single most common source of confusion. Change has a direction (positive or negative) and uses the original value as the base — '120 is 20% more than 100'. Difference is symmetric and uses the average of both values, so 80 vs 100 and 100 vs 80 give the same number (22.22%). Use 'change' for time-series questions (price went up, salary went down). Use 'difference' for comparing two unrelated values (compare two products). The fourth gotcha is stacked percentages: a 30%-then-10% discount is not 40% off — it's 0.70 × 0.90 = 63% kept, i.e. 37% off. Always multiply 'kept fractions' for stacks, never add percentages. Pick the operation below and the calculator handles the formula choice for you, plus shows a clean breakdown of the working.
Formula
Varies by mode — see the explanation above.
Example calculation
Example: 25% of 200 = 50
Set mode to 'X% of Y', X=25, Y=200. The calculator returns 50, which is one quarter of 200.
Frequently asked questions
Last reviewed: · Reviewed by the CalculatorHub editorial team.