KNOW THE MATH
How it works
Useful for tips, discounts and quick adjustments. Negative starting values and percentages are supported for general mathematical calculations.
Formula
X% of Y = (X ÷ 100) × Y. Increased value = Y × (1 + X ÷ 100). Decreased value = Y × (1 − X ÷ 100).
Worked example
15% of 250 is 37.5. Adding 15% gives 287.5; subtracting 15% gives 212.5.