Fraction calculator

Add, simplify, and convert fractions fast.

Last updated: January 10, 2026

Built and maintained by Aaron Jegla

Simplify fractions, combine them, and convert to decimals or percents in one place.

Perfect for homework checks, recipes, and quick ratio math.

Fraction details

Pick the fraction task you want to solve.

Top number in the fraction.

Bottom number (cannot be 0).

For simplifying, comparing, and converting everyday fractions.

Not for algebraic fractions. For percent work, use the percentage calculator.

How to use this calculator
  1. Choose the fraction task you need.
  2. Enter numerators and denominators for each fraction.
  3. Select Calculate to see simplified results.

Use Reset to return to the default examples.

Summary

Results are simplified to lowest terms.

Simplified fraction

0

Mixed number

0

Decimal

0

Percent

0%

Mode: Simplify | Formula: numerator and denominator divided by their GCD

Sources: OpenStax Prealgebra: Introduction to Fractions, Math is Fun adding fractions, Khan Academy fraction arithmetic

Assumptions: Fractions are reduced to lowest terms using the greatest common divisor. Negative signs are stored in the numerator and denominators are kept positive. Decimals are rounded to four places.

Disclaimer: Results are mathematically exact based on inputs. Verify inputs for accuracy.

How this calculator works

Each mode uses a standard fraction formula with simplified results.

Simplify: Divide numerator and denominator by their greatest common divisor.

Add or subtract: a/b +/- c/d = (ad +/- bc) / bd.

Multiply: (a/b) x (c/d) = (ac) / (bd).

Divide: (a/b) / (c/d) = (a x d) / (b x c).

Convert: Decimal = numerator / denominator; Percent = decimal x 100.

Results are always reduced to lowest terms for readability.

Fraction tips and assumptions

Quick context to interpret results and avoid common mistakes.

Denominators cannot be zero

Division by zero is undefined, so denominators must be non-zero.

  • Check for missing values.
  • Use whole numbers for best clarity.

Simplify whenever you can

Reducing before and after operations keeps numbers small.

  • Lowest terms are easier to compare.
  • Results stay exact without rounding.

Mixed numbers vs improper fractions

Both represent the same value, just in different formats.

  • Improper fractions are standard for math.
  • Mixed numbers are easier to read.

Negative fractions stay consistent

Signs are stored in the numerator to keep denominators positive.

  • -3/4 equals 3/-4.
  • The calculator standardizes the sign.

Fraction examples

Quick, step-by-step examples for each mode.

Example: Simplify 8/12

  1. Find the GCD of 8 and 12: 4.
  2. Divide both by 4 to get 2/3.

Example: 1/4 + 2/3

  1. Cross-multiply: (1 x 3) + (2 x 4) = 11.
  2. Multiply denominators: 4 x 3 = 12.

Example: 3/5 x 4/7

  1. Multiply numerators: 3 x 4 = 12.
  2. Multiply denominators: 5 x 7 = 35.

Example: Convert 7/4

  1. Divide 7 by 4 to get 1.75.
  2. Mixed number is 1 3/4.

When to use a fraction calculator

Use this calculator when you need exact fraction results instead of rounded decimals, such as homework checks, cooking ratios, or measurement conversions.

Fraction calculator FAQs

Click a question to expand the answer.

How do I simplify a fraction?

Divide the numerator and denominator by their greatest common divisor (GCD). The calculator finds the GCD and reduces the fraction for you.

Why can the denominator never be 0?

A fraction with a denominator of 0 is undefined because division by zero is not allowed. The calculator requires a non-zero denominator.

Does the calculator show mixed numbers?

Yes. Results include a simplified mixed number when the fraction is improper.

How does fraction division work?

Dividing by a fraction means multiplying by its reciprocal. For example, a/b divided by c/d equals (a/b) x (d/c).

How are decimal and percent results rounded?

Decimals are rounded to four places and percents to two places for readability. Use the fraction form when exact precision matters.

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