Fraction Calculator
Add, subtract, multiply, and divide fractions and mixed numbers, simplify fractions, and convert between fractions and decimals.
Fraction Calculator
Add, subtract, multiply, or divide two fractions. Results are automatically simplified.
Example: 3/4 + 1/6 = 11/12
Mixed Numbers Calculator
Add, subtract, multiply, or divide two mixed numbers, e.g. -2 3/4.
Example: -2 3/4 + 3 5/7 = 27/28
Simplify Fractions Calculator
Reduce a fraction — or a whole number plus a fraction — to its simplest form.
Example: 2 21/98 simplifies to 2 3/14
Decimal to Fraction Calculator
Convert a decimal number into a fraction in lowest terms.
Example: 1.375 = 1 3/8
Fraction to Decimal Calculator
Convert a fraction into its decimal equivalent.
Example: 2/7 ≈ 0.2857142857
Big Number Fraction Calculator
Use this calculator if the numerators or denominators are very large integers.
Example: 999999999999999999/1 + 1/1 = 1000000000000000000/1
How Fraction Operations Work
Unlike whole numbers, fractions need a common denominator before you can add or subtract them. Multiplying the numerator and denominator of each fraction by the other fraction's denominator creates that common denominator: a/b + c/d = (ad + bc)/(bd). For example, 3/4 + 1/6 = (3×6 + 1×4)/(4×6) = 22/24 = 11/12.
Multiplying fractions is direct — multiply the numerators together and the denominators together: a/b × c/d = ac/bd. Dividing is the same as multiplying by the reciprocal (flipping the second fraction): a/b ÷ c/d = a/b × d/c = ad/bc. For example, 3/4 ÷ 1/6 = 3/4 × 6/1 = 18/4 = 9/2.
A fraction is in simplest form when its numerator and denominator share no common factor other than 1. To simplify, divide both by their greatest common factor (GCF). For example, 220/440 has a GCF of 220, so it simplifies to 1/2.
To convert a decimal to a fraction, use the place value of the last digit as the denominator — 0.375 has 3 decimal places, so it becomes 375/1000, which simplifies to 3/8. To convert a fraction to a decimal, divide the numerator by the denominator using long division.
Frequently Asked Questions
About this calculator
This fraction calculator brings together every common fraction operation in one place: basic fraction arithmetic, mixed-number arithmetic, simplifying fractions to lowest terms, and converting between decimals and fractions in both directions. A dedicated big-number mode handles fractions with extremely large numerators or denominators using exact integer math, so results are never rounded due to floating-point limits.
- Fraction arithmetic — Add, subtract, multiply, or divide two fractions, with results automatically reduced to lowest terms.
- Mixed numbers — Work directly with mixed numbers like -2 3/4, without converting to improper fractions by hand.
- Simplify fractions — Reduce any fraction — or a whole number plus a fraction — to its simplest form using the greatest common factor.
- Decimal conversion — Convert decimals to exact fractions and fractions to decimals, in either direction.
- Big number mode — Uses exact arbitrary-precision integer math for fractions with very large numerators or denominators, avoiding floating-point rounding errors.