Fraction Calculator | Add, Subtract & Simplify

Quick Start Guide

  1. Select mode: Choose what you want to do (Convert to Decimal, Convert to Fraction, Simplify, or an Operations mode like Add/Subtract/Multiply/Divide).
  2. Enter values: Type numerator and denominator for fractions, or a decimal for conversion.
  3. View your result: See the converted, simplified, or calculated result update automatically as you type.
  4. Use mixed numbers (optional): Toggle to show results as mixed numbers (e.g., 1 1/2) instead of an improper fraction.
  5. Copy your result: Copy the fraction or decimal to your clipboard.
  6. Export your results: Save calculations to JSON, CSV, or PDF.

Understanding Fractions

Simple / Operations

Simple mode covers the three most common tasks — fraction to decimal, decimal to fraction, and simplifying. Operations mode adds two-fraction arithmetic (add, subtract, multiply, divide). Every mode always shows a visual bar, circle, and grid representation alongside the result.

Why common denominators matter

Adding or subtracting fractions requires a shared denominator because you can only combine parts that are the same size — 1/3 and 1/4 describe differently-sized pieces until both are rewritten over a common denominator (12, in this case). Multiplication and division don't need this step, which is why their formulas look simpler.

Mixed numbers are a display choice

"Use Mixed Numbers" doesn't change the underlying math — 7/4 and 1 3/4 are the same value. Toggling it changes how a whole-plus-fraction input is interpreted, and how a fraction result larger than 1 is displayed.

What this calculator does not cover

This handles two-fraction arithmetic and basic conversions — it does not solve fraction word problems or algebraic fraction expressions. For percentage-based math instead of fraction-based math, see the Percentage Calculator.

Features

Modes: Choose from Add/Subtract/Multiply/Divide, Simplify, Convert to Decimal, or Convert to Fraction.

Simplify: Reduces a fraction to its lowest terms using the greatest common divisor.

Arithmetic: Uses standard fraction rules — finds common denominators for addition and subtraction, multiplies numerators and denominators directly for multiplication, and inverts for division.

Common Use Cases

Cooking & Baking: scale recipes up or down and combine fractional measurements.

Math Homework: practice and verify fraction arithmetic, and simplify fractions to lowest terms.

Measurements & DIY: add fractional lengths (e.g. 3/4 + 1/8 inch) for building and craft projects.

Finance & Ratios: express proportions as simplified fractions and calculate odds, probabilities, and splits.

Frequently Asked Questions

Select the 'Fraction to Decimal' operation, enter the numerator and denominator, and the calculator shows the decimal equivalent. For example, 3/4 = 0.75. The result updates automatically as you type.
Write the decimal over 1 (e.g., 0.75/1), multiply both top and bottom by 10, 100, or 1000 to eliminate the decimal (75/100), then simplify by dividing by GCD (3/4). This calculator converts instantly in both directions.
Find the least common denominator (LCD), convert each fraction to have that denominator, then add the numerators and keep the denominator. Example: 1/3 + 1/4 → LCD=12 → 4/12 + 3/12 = 7/12. Simplify the result if possible.
Multiply numerators together and denominators together: (a/b) × (c/d) = (a×c)/(b×d). Example: 2/3 × 3/4 = 6/12 = 1/2. Always simplify the result. Cross-cancellation before multiplying can make the numbers smaller and easier to work with.
Flip the second fraction (find its reciprocal), then multiply: (a/b) ÷ (c/d) = (a/b) × (d/c). Example: 3/4 ÷ 2/5 = 3/4 × 5/2 = 15/8 = 1 7/8. Enter any fraction division in this calculator for step-by-step results.
Divide both the numerator and denominator by their greatest common divisor (GCD). For 12/18, the GCD is 6, so it simplifies to 2/3. The calculator reduces any fraction to lowest terms automatically and shows the equivalent decimal alongside a visual bar/circle/grid representation.
Mixed numbers combine whole numbers with fractions (e.g., 1 1/2 instead of 3/2). Enable 'Use Mixed Numbers' to see results in mixed number format. This is useful for measurements and everyday use.

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