Multiply Y by X expressed as a decimal:
result = Y × (X ÷ 100)
Example:
1,000 × (50 ÷ 100) = 500
Divide X by Y, then convert to a percentage:
result = (X ÷ Y) × 100
Example:
(50 ÷ 1,000) × 100 = 5%
Take the change (Y − X), divide by the starting value X, then convert to a percentage:
result = ((Y − X) ÷ X) × 100
Example:
((1,000 − 50) ÷ 50) × 100 = 1,900%
Divide Y by X expressed as a decimal:
result = Y ÷ (X ÷ 100)
Example:
50 ÷ (25 ÷ 100) = 200
Add (or subtract) Y% of X to (or from) X:
result = X ± X × (Y ÷ 100)
Useful for tax, tip, markup, and discount.
Example:
100 + 10% = 110
100 − 10% = 90