ohformation KO · EN
Everyday · Percentage

Percentage Calculator

Four questions, one screen.

Reading your result

Fill in every field and the steps will be spelled out here.

How it is calculated

B% of A = A × B ÷ 100 A as % of B = A ÷ B × 100 Percent change = (B − A) ÷ A × 100 Discounted = A × (100 − B) ÷ 100

Percent and percentage point are not the same thing. A rate moving from 3% to 5% has risen by 2 percentage points, which is a 67% increase in relative terms. When a figure is itself a percentage, saying "up 2%" is ambiguous. The change mode here reports relative change.

Two discounts do not add up. 20% off followed by another 10% off is not 30% off — it is 28% off, because the second cut applies to an already reduced price. The same logic works against you in reverse: a 20% rise followed by a 20% fall leaves you 4% below where you started.

Increases and decreases are not symmetric. Going from 100 to 50 is a 50% decrease; going back from 50 to 100 is a 100% increase. The size of the move is identical but the base is not, which is where most misreadings of growth figures come from.

Frequently asked questions

What is the difference between % and percentage points?

Percentage points describe the arithmetic gap between two rates; percent describes the change relative to the starting value. From 3% to 5% is 2 percentage points, or roughly a 67% increase.

Is 20% off twice the same as 40% off?

No — it works out to 36% off. The second reduction applies to the already discounted price, so 10,000 becomes 8,000 and then 6,400.

Does a 20% rise then a 20% fall cancel out?

No. 100 rises to 120, then a 20% fall takes it to 96 — 4% below the original. The two moves are measured against different bases.

These are plain arithmetic results. Actual transaction amounts may differ once taxes, fees and rounding rules are applied.