Percentage multipliers
Percentage multipliers are a quick and powerful way to increase or decrease amounts in one step—like adding 20% VAT to a shopping bill or working out a 15% discount during a sale. Instead of doing two separate steps (finding the percentage, then adding or subtracting it), percentage multipliers let you do it all in one go with a single calculation. Jump to the questions
Practise now
Enter the multiplier for each percentage change:
Topic guide
What this worksheet practises
This worksheet focuses purely on creating the correct decimal multiplier for a specific percentage change. Mastering multipliers is essential for answering compound interest and reverse percentage questions efficiently.
Key method
A multiplier is just a percentage written as a decimal, but it is always based around the original 100%.
- Finding a percentage of an amount: Simply divide the percentage by 100. (e.g. finding 42% uses the multiplier 0.42).
- Increasing by a percentage: Add the percentage to 100%, then divide by 100. (e.g. a 15% increase means you have 115%. The multiplier is 1.15).
- Decreasing by a percentage: Subtract the percentage from 100%, then divide by 100. (e.g. a 20% decrease means you have 80% left over. The multiplier is 0.80).
Worked example
Write down the decimal multiplier for:
1) A 6% increase.
2) A 35% decrease.
3) A 2.5% increase.
Example 1: 100% + 6% = 106%. Divide by 100 to get the decimal: 1.06.
Example 2: 100% − 35% = 65%. Divide by 100 to get the decimal: 0.65.
Example 3: 100% + 2.5% = 102.5%. Divide by 100 to get the decimal: 1.025.
Common mistakes to avoid
The most common mistake is dealing with single-digit percentage increases. If asked for a 4% increase multiplier, students often write 1.4 (which is actually a massive 40% increase) instead of the correct 1.04. Remember that the hundreds column is the whole amount, the tenths column is 10s of percent, and the hundredths column is single percents.
How to check your answer
Any multiplier for an increase must be greater than 1. Any multiplier for a decrease must be less than 1. Any multiplier for finding a simple fraction of an amount must be less than 1.