Question 1

How do I calculate a percentage increase?

Accepted Answer

Subtract the old value from the new value, divide by the old value, then multiply by 100. Example: from 80 to 100 is (100-80)/80 × 100 = 25% increase.

Question 2

What does per cent mean?

Accepted Answer

Per cent comes from the Latin 'per centum', meaning 'by the hundred'. A percentage is simply a ratio expressed as a fraction of 100.