Fraction Calculator

What is a fraction calculator?

A fraction calculator adds, subtracts, multiplies and divides fractions and mixed numbers and gives the answer in its simplest form. Type each fraction as a whole number, a numerator and a denominator, choose the operation, and the calculator shows the result as a reduced fraction, a mixed number, a decimal and a percentage – plus a step-by-step solution you can copy into your notebook. It is a free fraction calculator with steps for students, parents, teachers, cooks and anyone measuring in inches.

What is a fraction in maths?

A fraction describes a part of a whole. It is written as numerator / denominator: the denominator (bottom number) says how many equal parts the whole is divided into, and the numerator (top number) says how many of those parts you have. 3/4 means three of four equal parts. A proper fraction has a smaller numerator than denominator (3/4); an improper fraction has a numerator equal to or larger than the denominator (7/4); and a mixed number combines a whole number with a proper fraction (1 3/4).

How to use the fraction calculator

1. Enter the first fraction. For a mixed number such as 1 3/4, type 1 as the whole number, 3 as the numerator and 4 as the denominator. For a simple fraction leave the whole number at 0.
2. Pick the operation: add, subtract, multiply or divide.
3. Enter the second fraction the same way. To use a whole number, type it as the numerator with 1 as the denominator (for example 5/1) – that is how the fraction calculator with whole numbers works.
4. Read the answer and open the step-by-step table to see each stage of the working.

For negative fractions, put the minus sign on the whole number (−2 1/3) or on the numerator (−5/6). The calculator handles negative and positive fractions together.

Fraction formulas

a/b + c/d = (ad + bc) / bd  ·  a/b − c/d = (ad − bc) / bd

a/b × c/d = ac / bd  ·  a/b ÷ c/d = a/b × d/c = ad / bc

• a, c = numerators; b, d = denominators (never zero)
• For addition and subtraction the calculator uses the least common denominator (LCD) instead of b × d, which keeps the numbers small.
• Every answer is then reduced by dividing the top and bottom by their greatest common divisor (GCD).

Adding fractions (fraction calculator addition)

To add fractions with unlike denominators, first rewrite them with a common denominator. Example – the default in the calculator: 1 3/4 + 5/6.

1. Convert the mixed number to an improper fraction: 1 3/4 = (1 × 4 + 3)/4 = 7/4.
2. Find the LCD of 4 and 6, which is 12 (the LCM calculator shows how).
3. Rewrite: 7/4 = 21/12 and 5/6 = 10/12.
4. Add the numerators: 21 + 10 = 31, so the sum is 31/12.
5. 31/12 is already in lowest terms; as a mixed number it is 2 7/12, and as a decimal 2.583333.

Subtracting fractions

Subtraction follows the same steps: 5/6 − 1/4 → LCD 12 → 10/12 − 3/12 = 7/12. With mixed numbers, converting both to improper fractions first avoids the "borrowing" mistakes that happen when the second fraction part is bigger than the first: 3 1/5 − 1 2/3 = 16/5 − 5/3 = 48/15 − 25/15 = 23/15 = 1 8/15.

Multiplying fractions

Multiply the numerators together and the denominators together, then simplify. 2/3 × 9/10 = 18/30 = 3/5. To multiply a fraction by a whole number, write the whole number over 1: 3/8 × 4 = 12/8 = 1 1/2. Mixed numbers must be turned into improper fractions first: 2 1/2 × 1 1/3 = 5/2 × 4/3 = 20/6 = 3 1/3.

Dividing fractions

Dividing by a fraction is the same as multiplying by its reciprocal – "keep, change, flip". 3/4 ÷ 2/5 = 3/4 × 5/2 = 15/8 = 1 7/8. You cannot divide by zero, so the second fraction must not equal 0.

Simplifying fractions to lowest terms

To reduce a fraction to lowest terms, divide the numerator and denominator by their greatest common divisor. 24/36 has GCD 12, so it simplifies to 2/3. Fractions that look different but reduce to the same simplest form are called equivalent fractions – 2/3, 4/6, 8/12 and 24/36 are all equivalent. To simplify a single fraction here, enter it as the first fraction and multiply it by 1/1.

Fraction to decimal and percentage

To convert a fraction to a decimal, divide the numerator by the denominator: 7/8 = 7 ÷ 8 = 0.875. To convert a fraction to percentage, multiply the decimal by 100: 0.875 × 100 = 87.5%. The calculator shows both for every answer. Some fractions give repeating decimals – 1/3 = 0.333… and 2/7 = 0.285714… – so the fraction form is exact while the decimal is rounded.

How to calculate a fraction of a number

Multiply the number by the numerator and divide by the denominator. 3/5 of 250 = 250 × 3 ÷ 5 = 150. In the calculator, enter 3/5 × 250/1. This is the same idea as a percentage – 3/5 is 60% – so the percentage calculator gives the same answer.

The butterfly method

The butterfly method is a quick way to add or subtract two fractions by hand: multiply diagonally (a × d and b × c) for the new numerators, multiply the denominators (b × d) for the new denominator, then add or subtract and simplify. For 2/3 + 1/4: 2 × 4 = 8, 3 × 1 = 3, 3 × 4 = 12, giving 11/12. It always works, but with larger denominators it creates big numbers, so the LCD method used by this calculator is tidier.

Fractions for measurements, inches and baking

Fractions are everywhere in woodworking, construction and recipes. On an imperial tape measure, 1 1/2 in + 3/8 in = 12/8 + 3/8 = 15/8 = 1 7/8 inches. To halve a recipe that needs 3/4 cup of sugar, multiply 3/4 × 1/2 = 3/8 cup. For three or more fractions, work in pairs: add the first two, then add the third fraction to that answer.

How to do fractions on a calculator

Most scientific calculators have a fraction key (a b/c or ◻/◻). On a basic calculator without one, divide the numerator by the denominator to get a decimal, and use brackets for the whole problem: (3 ÷ 4) + (5 ÷ 6). You lose the exact fraction form, which is why a dedicated fraction calculator like this one – or the scientific calculator for the decimal value – is easier.

Fraction calculator formula summary

The fraction calculator formula for each operation is short. Add: a/b + c/d = (ad + bc)/bd. Subtract: (ad − bc)/bd. Multiply: ac/bd. Divide: a/b ÷ c/d = ad/bc. The calculator then divides the top and bottom by their greatest common factor to simplify.

Fraction calculator division example

For division, the fraction calculator flips the second fraction and multiplies: 3/4 ÷ 5/6 = 3/4 × 6/5 = 18/20 = 9/10.

Fraction calculator to simplify, reduce and find lowest terms

Every answer here is simplified and reduced to lowest terms automatically. To reduce a fraction by hand, divide the numerator and denominator by their greatest common factor: 42/56 has GCF 14, so it reduces to 3/4. To simplify a single fraction, enter it as the first fraction, choose × and enter 1/1 as the second.

Fraction calculator for equivalent fractions

Equivalent fractions have the same value: 1/2 = 2/4 = 50/100. Multiply or divide the top and bottom by the same number. A fraction calculator shows two fractions are equivalent when both simplify to the same lowest-terms answer.

Fraction calculator to percent

To convert with a fraction calculator to percent, divide the numerator by the denominator and multiply by 100: 3/8 = 0.375 = 37.5%.

Fraction calculator for 3 fractions

To add or multiply 3 fractions, do two steps. For 1/2 + 1/3 + 1/4, first find 1/2 + 1/3 = 5/6, then enter 5/6 + 1/4 = 13/12 = 1 1/12. The order does not matter for addition or multiplication.

Fraction calculator for construction, woodworking and measurements

Tape measures in inches are marked in halves, quarters, eighths and sixteenths, so a fraction calculator for construction and woodworking saves mistakes. Cutting 2 3/8 in and 1 11/16 in from one board uses 2 3/8 + 1 11/16 = 4 1/16 inches; enter the whole numbers in the mixed-number boxes.

Fraction calculator for feet and inches

For feet and inches, convert everything to inches first (1 ft = 12 in). 5 ft 3 1/2 in minus 2 ft 8 3/4 in is 63 1/2 − 32 3/4 = 30 3/4 in, which is 2 ft 6 3/4 in.

Fraction calculator for baking

To halve a recipe that needs 3/4 cup of sugar, multiply by 1/2: 3/8 cup. To make 1 1/2 times a recipe needing 2/3 cup of flour: 2/3 × 3/2 = 1 cup. A fraction calculator for baking keeps these amounts exact.

Fraction calculator equation: solve for x with variables

This fraction calculator works with numbers, not variables, but it helps you solve fraction equations step by step. To solve x/4 + 1/3 = 5/6 for x: subtract 1/3 from both sides (5/6 − 1/3 = 1/2), so x/4 = 1/2 and x = 2. With x and y in a fraction, such as (2x)/(3y), you multiply and simplify the same way, treating the variables like numbers you cannot combine.

Fraction calculator with exponents and pi

For exponents, raise the top and bottom separately: (2/3)³ = 8/27, and a negative exponent flips the fraction: (2/3)⁻² = 9/4. For pi, a common fraction approximation is 22/7 ≈ 3.1429, and 355/113 is closer; pi itself cannot be written exactly as a fraction.

Can you do fractions on a calculator?

Yes. Many school scientific calculators have a fraction button (marked a b/c or ▭/▭). On a basic calculator, divide the top by the bottom to get a decimal. This online fraction calculator needs no app or download and is free on any phone, so you get a fraction calculator app free of installs.

Fraction calculator for kids: year 4 practice questions

Children in year 4 learn to add and subtract fractions with the same denominator and to find equivalent fractions. Kids can use the fraction calculator to check answers after working them out on paper. Try these fraction calculator questions:

1. 2/7 + 3/7 = 5/7
2. 5/8 − 1/4 = 5/8 − 2/8 = 3/8
3. 2/3 × 9/10 = 18/30 = 3/5
4. Is 6/9 equivalent to 2/3? Yes, both reduce to 2/3.

Frequently asked questions

Last updated 2026-09-18