Percentage of a number:
result = (part ÷ whole) × 100
Convert a percentage to a number:
result = percentage × (whole ÷ 100)
Find the part given the whole and percentage:
part = whole × (percentage ÷ 100)
Find the whole given the part and percentage:
whole = part ÷ (percentage ÷ 100)
Percentage change (increase/decrease):
change% = ((new − old) ÷ old) × 100
Difference as a percentage of the original:
percent = ((A − B) ÷ B) × 100
Percentage points (not relative change):
points = percentage1 − percentage2
Add/subtract a percentage from a number:
new = original × (1 ± percentage ÷ 100)
If result is a fraction and you need percent:
percent = (numerator ÷ denominator) × 100