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Simplify Fractions Calculator: Lowest Terms, Mixed Number, Decimal

A fraction in lowest terms with the common factor shown, plus its mixed number, decimal and percentage.

Inputs

Simplified
3/4

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What each Simplify Fractions input means

Numerator
The top number — how many of the equal parts you have. Whole numbers only, negatives allowed. For a fraction with a decimal in it, such as 2.5/4, multiply both numbers by 10 first and enter 25/40.
Denominator
The bottom number — how many equal parts make one whole. It cannot be 0. A negative denominator is fine: the sign moves to the top, so 3/−12 comes out as −1/4.

Simplify Fractions formula

simplified = (numerator ÷ GCF) / (denominator ÷ GCF), where GCF is the greatest common factor

ab=a÷gb÷g,g=gcd⁡(a,b)\frac{a}{b} = \frac{a \div g}{b \div g}, \quad g = \gcd(a, b)

A fraction is in lowest terms when the top and bottom share no factor but 1. OpenStax's method is to write both as products of their factors and remove the factors they share — the Equivalent Fractions Property says that does not change the value. Doing it in one step means dividing both by their greatest common factor: 18/24 shares a 6, so it is 3/4. The page shows that factor, then the fraction as a mixed number when it is more than 1, as a decimal and as a percentage.

Simplify Fractions worked example

18 and 24 are both divisible by 6, their greatest common factor: 18 ÷ 6 = 3 and 24 ÷ 6 = 4, so 18/24 = 3/4 — 0.75, or 75%. OpenStax's example, 10/15, works the same way with a common factor of 5: 2/3.

More Simplify Fractions examples

45 minutes out of an hour, 45/60. The greatest common factor of 45 and 60 is 15, and 45 ÷ 15 = 3 while 60 ÷ 15 = 4, so it is 3/4 of an hour: 0.75, or 75%. Dividing by a smaller shared factor first, such as 5 (giving 9/12), also works; it just needs a second step, ÷ 3, to finish.

An improper fraction, 22/8. Both numbers are even and 2 is their greatest common factor, so it reduces to 11/4. As a mixed number that is 2 3/4, because 4 goes into 11 twice with 3 left over; as a decimal it is 2.75.

Where the Simplify Fractions calculator can give the wrong answer

  • A denominator of zero is rejected; division by zero is undefined.
  • The sign is kept on the numerator: −3/12 becomes −1/4.
  • Improper fractions are shown as a mixed number too: 7/4 is 1 3/4.
  • Only whole-number numerators and denominators are simplified; for a decimal like 0.375, use the decimal-to-fraction calculator.

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Simplify Fractions reference table

Common fractions as decimals and percentages
FractionDecimalPercent
1/20.550%
1/30.333…33.33%
2/30.666…66.67%
1/40.2525%
3/40.7575%
1/50.220%
1/60.1666…16.67%
1/80.12512.5%
3/80.37537.5%
5/80.62562.5%
7/80.87587.5%
1/100.110%
1/120.0833…8.33%
1/160.06256.25%
Source: Arithmetic: numerator ÷ denominator, and × 100 for the percentage; … marks a decimal that repeats forever, and those percentages are rounded to two places

Simplify Fractions FAQ

Divide the numerator and denominator by their greatest common factor. 18/24: the GCF is 6, so 3/4.