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How to Convert Fractions to Decimals

In one line: To turn a fraction into a decimal, divide the top number (the numerator) by the bottom number (the denominator), because a fraction is really a division waiting to happen.

Why it works

Fractions and decimals are two ways of writing the same amount, and everyday life uses both. Prices, measurements in metres and centimetres, and calculator answers all use decimals, while recipes and sharing problems often use fractions. Being able to switch between them makes it easy to compare amounts. For example, 3/8 and 0.4 are hard to compare until you see that 3/8 is 0.375, which is smaller than 0.4.

Think of it like: Think of the fraction 3/8 as 3 chocolate bars shared equally among 8 friends. Each friend can't get a whole bar, so you cut the bars into smaller pieces and keep sharing until nothing is left. Dividing 3 by 8 is exactly that sharing, and the answer, 0.375, tells you how much of one bar each friend gets. (Where this breaks: Real chocolate always runs out, but some divisions never finish. Sharing 1 bar among 3 people gives 0.333… where the 3s go on forever, called a recurring decimal. You would never be able to cut the chocolate that finely, but in maths the pattern really does continue without end.)

Worked example

Convert 3/8 into a decimal.

  1. Read the fraction as a division: 3/8 means 3 ÷ 8.
  2. 8 does not go into 3, so write 3 as 3.000 and put a decimal point in your answer straight above the one in 3.000: 0.
  3. 8 into 30 goes 3 times (24) with 6 left over, so write 3 after the decimal point: 0.3
  4. Bring down a 0 to make 60. 8 into 60 goes 7 times (56) with 4 left over: 0.37
  5. Bring down another 0 to make 40. 8 into 40 goes exactly 5 times with nothing left over: 0.375
  6. Check: 375/1000 simplifies to 3/8, so the answer is right.

Answer: 3/8 = 0.375

Common mistakes

  • Writing 3/8 as 3.8 by just putting a dot between the numbers; instead, always divide the top number by the bottom number.
  • Dividing the wrong way round, such as 8 ÷ 3 instead of 3 ÷ 8; remember a proper fraction (top smaller than bottom) always gives a decimal less than 1.
  • Forgetting a placeholder zero, such as writing 1/20 as 0.5 instead of 0.05; check by turning the fraction into hundredths first (1/20 = 5/100 = 0.05).
  • Stopping a recurring decimal early and calling it exact, such as saying 1/3 = 0.3; write 0.333… or put a dot over the repeating digit to show it goes on forever.

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What is 1/4 as a decimal?

Questions parents ask

What year do kids learn to convert fractions to decimals?

In the UK, children meet simple ones like 1/2 = 0.5 and 1/4 = 0.25 in Year 4 and learn to use division for fractions such as 3/8 in Year 6. In Australia it is built up across Years 5 to 7. In the US, Grade 4 covers tenths and hundredths, and Grade 7 uses long division to convert any fraction, including recurring decimals.

How can I help my child convert fractions to decimals at home?

Use money: 1/4 of £1 is 25p, or £0.25, which makes the link feel real. Practise a few key facts together, such as halves, quarters, fifths and tenths, then move on to dividing with short division. Let your child check answers on a calculator afterwards rather than before.

Why do some fractions turn into decimals that never end?

When you divide, the remainders can start repeating, so the digits repeat too, as in 1/3 = 0.333…. This happens whenever the simplified fraction's denominator has a prime factor other than 2 or 5. Fractions like 1/8 or 3/20 always finish, while 1/3, 1/6 and 1/7 go on forever.

Which fraction-to-decimal facts should my child know by heart?

The most useful ones are 1/2 = 0.5, 1/4 = 0.25, 3/4 = 0.75, 1/5 = 0.2, 1/10 = 0.1 and 1/8 = 0.125. Knowing 1/3 = 0.333… and 2/3 = 0.666… also helps. These come up constantly in measuring, money and percentages, so knowing them saves a lot of time.