How do you add fractions?

To add fractions, find the lowest common denominator (LCD), convert both fractions to that denominator, then add the numerators and simplify.

How do I simplify a fraction?

Divide both numerator and denominator by their greatest common divisor (GCD). The calculator does this automatically.

Can I enter mixed numbers?

Enter the whole number in the first box. For example, 2½ would be whole=2, numerator=1, denominator=2.

Fraction Calculator

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About the Fraction Calculator

What it does

Performs addition, subtraction, multiplication, and division on any two fractions and displays the result both as a simplified fraction and as a decimal. All answers are automatically reduced to lowest terms.

How fractions work

A fraction represents a part of a whole: the numerator (top) shows how many parts you have, and the denominator (bottom) shows how many equal parts the whole is divided into.

Simplification The result is reduced by dividing both numerator and denominator by their greatest common divisor (GCD).
Improper fractions If the result has a numerator larger than the denominator, the decimal equivalent makes the value clear.

Fractions in cooking and measurement

Fractions appear constantly in cooking recipes (particularly American ones using cups and tablespoons), in woodworking and construction measurements, and in music (quarter note, eighth note time signatures). Being able to add or scale fractions quickly — doubling a recipe that calls for 3/4 cup means you need 1 1/2 cups — is a practical daily skill.

Recipe scaling — multiply all fractions by the scale factor; 3/4 cup x 2 = 6/4 = 1 1/2 cups
Imperial measurements — 3/4 + 1/2 inch = 9/12 + 6/12 = 15/12 = 1 3/12 = 1 1/4 inches
Music notation — a bar in 4/4 time holds fractions that sum to 1: four quarter notes = 4 x 1/4 = 1
Finance — bond prices are quoted in fractions (32nds) on US markets: 99-16/32 = 99.5

Frequently Asked Questions

What is the LCM (Lowest Common Multiple)?

The LCM is the smallest number that both denominators divide into evenly. When adding or subtracting fractions, both fractions must share the same denominator, so you convert them to an equivalent fraction with the LCM as the denominator.

How is fraction division done?

To divide by a fraction, you multiply by its reciprocal. For example, ½ ÷ ¾ = ½ × 4/3 = 4/6 = ⅔.

What is a mixed number?

A mixed number contains both a whole number and a fraction, like 2½. Enter the whole number separately — the calculator combines it with the fraction before computing.

How does the calculator simplify fractions?

The calculator uses the Greatest Common Divisor (GCD) algorithm to reduce fractions to their simplest form. For example, 6/8 simplifies to 3/4 because GCD(6,8) = 2. Results are always shown in fully simplified form.

Can I use mixed numbers like 1½?

Enter mixed numbers by converting them to improper fractions first. For example, 1½ becomes 3/2 (multiply the whole number by the denominator and add the numerator: 1×2+1 = 3). The calculator will simplify your result back to a mixed number if applicable.