What are benchmark percents?

Easy percents to find in your head: 50% (half), 25% (a quarter), 10% (÷ 10), 5% and 1% (÷ 100).

How do you find 10% of a number?

Divide by 10, which moves every digit one place right. 10% of 350 is 35.

How do you find 15% of a number?

Find 10%, then half of that for 5%, and add them. 15% of 40 is 4 + 2 = 6.

Why is 8% of 50 the same as 50% of 8?

Because percent of means multiply, and you can multiply in any order: 8/100 × 50 = 50/100 × 8 = 4.

What grade learns benchmark percents?

Grades 5 and 6 under Common Core 6.RP.A.3c. In India, class 7.

Benchmark percents

Benchmark percents are the easy ones: 50%, 25%, 10%, 5% and 1%. Use them to find any percent in your head. Quiz for kids, help below.

🧒 Kids: use the shortcuts!

50% is half, 25% is a quarter and 10% means divide by 10. Use these tricks in the quiz!

▶ Quiz 🔢 More practice

💡 Trick: 10% of 80 is 8. So 20% is 16, and 5% is 4!

More percents: What is a percent · Percent to fraction · Fraction to percent · Decimal to percent · Benchmark percents · Over 100% and under 1%

For parents and teachers ↓

This part is for grown-ups: the key idea, pictures to draw, what to say, common mistakes, questions with answers and a free worksheet.

The trick: half, quarter, tenth

A few percents are easy to find without a calculator. 50% is half, 25% is half of a half, and 10% is the number divided by 10. From 10% you get 5% (half of 10%), 20% (double 10%) and 1% (divide by 100). Almost any percent can be built from these pieces.

50% of 64: half: 32
25% of 64: half of 32: 16
10% of 64: ÷ 10: 6.4
15% of 40: 10% is 4, 5% is 2, so 6

Patterns to spot

50% is half and 25% is half again.
10% moves every digit one place right: 10% of 350 is 35.
1% moves every digit two places right: 1% of 350 is 3.5.
5% is half of 10%, and 20% is double 10%.
75% is 50% + 25%, or the whole minus 25%.
x% of y equals y% of x: 8% of 50 = 50% of 8 = 4.

See it: pictures to draw with your child

Draw these on paper or a whiteboard. A quick sketch makes the idea concrete before any rules.

50% of 80 is half of 80: 40.

25% is half of 50%: 20.

10% of 80 is 80 ÷ 10 = 8. Then 5% is 4, and 20% is 16.

What your child already knows

Children know how to halve numbers and divide by 10. They know that 50% is a half and 25% is a quarter. Benchmark percents turn these simple skills into a fast way to find any percent.

In real life: A $40 shirt at 25% off saves $10. A 10% tip on a $35 meal is $3.50, and a 15% tip adds half of that again: $5.25. Shoppers and waiters use these shortcuts every day.

Building any percent from the benchmarks

Most percents can be built from 50%, 25%, 10%, 5% and 1%. For example, 35% is 25% + 10%, or 3 × 10% + 5%. Children choose whichever pieces feel easiest.

Take 35% of 60. 10% of 60 is 6, so 30% is 18. 5% is half of 6, which is 3. So 35% of 60 is 18 + 3 = 21.

Benchmarks are also great for estimating. 48% is about half, so 48% of 300 is about 150. The percent calculator can check the exact answer.

Worked examples

Example 1: Half and quarter

Find 75% of 48. 50% is 24 and 25% is 12.
Add them: 75% of 48 is 36.

Example 2: Tens and fives

Find 15% of 120. 10% is 12 and 5% is half of that, 6.
So 15% is 18.

Example 3: Swap trick

Find 4% of 25.
Swap: 25% of 4 is 1.
So 4% of 25 is also 1.

Common mistakes

10% of 50 is 10Confuses the percent with the answer.Fix: 10% means divide by 10: 50 ÷ 10 = 5.

25% means divide by 25Uses the percent as a divisor.Fix: 25% is a quarter, so divide by 4.

1% of 300 is 30Divides by 10 instead of 100.Fix: 1% means divide by 100: 3.

What to say to your child

A short script for your first session. Pause after each line and let your child answer.

“What is half of 60?” (30.) “So 50% of 60 is 30.”
“What is half of 30?” (15.) “That is 25% of 60.”
“What is 60 ÷ 10?” (6.) “That is 10% of 60.”
“What would 20% be?” (12.)
“And 5%?” (Half of 6: 3.)

Questions to try (answers below)

Ask these out loud or write them down. The last one is a stretch.

50% of 90
25% of 80
10% of 250
1% of 400
5% of 60
20% of 45
75% of 40
15% of 200
Stretch: 35% of 60

Show the answers

Games to play at home

Shop sale

Pick toy prices and work out 10%, 25% and 50% off.

Tip helper

At a restaurant, let your child find the 10% and 15% tip.

Speed round

Call out “10% of 70!” and race to answer.

A 5-day plan for benchmark percents

Ten minutes a day is enough. Short, regular practice works far better than one long session.

Day 1: Learn it with real things: grid paper, prices, a battery icon or a test score, like the pictures above.
Day 2: Read the script together, then ask the first four questions.
Day 3: Do the quiz at the top of the page and read the hints for anything missed.
Day 4: Play one of the games above for ten minutes.
Day 5: Ask the rest of the questions, then do a round of the matching percent practice skill.

By grade

Grade 6 (Common Core 6.RP.A.3c) finds a percent of a quantity as a rate per 100. Grade 5 builds the halving and ÷ 10 skills behind it. Grade 7 uses benchmarks for tax, tips and discounts. In India, this comes in class 7 maths.

More for each grade: Grade 5 math and the CBSE class 5 maths guide; Grade 6 math and the CBSE class 6 maths guide.

What comes next

Use the benchmarks to find any percent of a number, then work out what percent one number is of another. For percents bigger than 100%, see over 100% and under 1%.

Worksheet and more practice

Print a free worksheet with an answer key, or keep practicing online with percent practice.

← Decimal to percent Over 100% and under 1% →

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