Finding five percent of an amount
Working out 5% of an amount is a handy skill—whether you're grabbing a 5% discount in a sale, calculating tips, or splitting a cost. It’s a small percentage, but knowing how to find it quickly can save time and money in everyday situations. Jump to the questions
Practise now
Topic guide
What this worksheet practises
This worksheet focuses on a core mental arithmetic skill: finding exactly 5% of a given amount. Being able to quickly calculate 5% without a calculator is incredibly useful for figuring out discounts, interest, or tips.
Key method
You shouldn't try to calculate 5% directly. Instead, use 10% as a stepping stone.
- First, find 10% of your starting amount. You do this by dividing the number by 10 (which moves the decimal point one place to the left).
- Second, because 5 is exactly half of 10, simply halve your 10% answer to find 5%.
Worked example
Find 5% of £420.
Step 1: Find 10% by dividing by 10.
10% of 420 = 420 ÷ 10 = 42.
Step 2: Halve the 10% amount to find 5%.
Half of 42 is 21.
5% of £420 is £21.
Common mistakes to avoid
The most common mistake is forgetting the second step and giving the 10% value as the final answer. Another error is dividing by 5 initially instead of 10. Dividing an amount by 5 actually gives you 20%, not 5%. Always go through 10% first.
Things to remember
This "stepping stone" method is extremely versatile. Once you know 10% and 5%, you can build almost any arithmetic percentage mentally. Need 15%? Just add your 10% and 5% answers together. Need 2.5%? Halve your 5% answer.