Guides · Percentage
Three percentage problems
Most “percent calculator” searches are one of these. CalcKit keeps them on one page with three tabs.
X% of Y
Result = Y × (X ÷ 100). 18% of 80 is 14.4. The percent can be larger than 100.
What percent is X of Y
Result = (X ÷ Y) × 100. 18 is 20% of 90. If Y is 0 the result is undefined — the tool does not print Infinity.
Percent change
((new − original) ÷ original) × 100. 80 → 100 is +25%. 100 → 80 is −20%. Those are not the same magnitude in reverse, because the denominator changed. Original 0 is undefined.
Open the percentage calculator.