Percentage Calculator

Five ways to work with percentages

Percentage math covers more than just "what is X percent of Y." This calculator brings together the five most common variants in one place, so you don't have to hunt for the right formula for your specific question.

The five variants, with examples

Percent of a number: 15% of 850 = (15/100) × 850 = 127.5. Used to find a share of a value, like a commission or a portion of a budget.

What percentage: 200 of 850 = (200/850) × 100 ≈ 23.5%. Flips the question, you have the part and the whole, and want to know how large a share that is.

Percentage change: from 850 to 920 = ((920−850)/850) × 100 ≈ 8.2% increase. Compares two values and shows the change as a percentage, with direction (increase or decrease).

Discount: 850 at a 15% discount = 850 − (850 × 0.15) = 722.5. Subtracts a percentage from a price and shows both the new price and the amount saved.

VAT: 850 excluding VAT with 25% VAT = 850 + (850 × 0.25) = 1,062.5. Adds a percentage on top of a price, the opposite of a discount.

Common mistake: percent vs percentage points

If a rate goes from 5% to 7%, it has risen by 2 percentage points, but by 40% in relative terms (2/5 × 100). The two ways of describing the same change get mixed up often, and which one is correct depends on context, so be explicit about which you mean.

Common uses

Percentage math shows up everywhere: discounts and VAT when shopping, tips at restaurants, grading in school, interest on loans and savings, and statistics in news and reports. These same five basic forms cover the vast majority of those situations.