Beginner · 10 min
Percentage increases and decreases
Calculate a change from the original amount.
Increase from the starting value
Find the percentage of the original value and add it. An increase of 20% leaves you with 120% of the original.
Worked example
50 increased by 20%: 50 × 1.20 = 60
Successive changes use new bases
A later percentage change applies to the new amount. Equal percentage increases and decreases do not generally cancel out.
Worked example
100 increased by 10% is 110; then reduced by 10% it is 99.
Compare two offers
- Calculate the price after a 25% reduction on 120.
- Find the percentage increase needed to return that reduced price to 120.