Least Common Denominator Calculator

The Least Common Denominator Calculator helps you quickly find the LCD for any group of fractions and convert them to equivalent forms. Whether you’re adding or comparing fractions, building math worksheets, or simplifying expressions, this tool gives you the LCD instantly with optional steps, formatting, and numerator previews. It’s perfect for students, teachers, and anyone needing fast fraction conversions.

Options
Reduce Inputs
Show Equivalent Numerators
Sort by Value

How to Use:

To use the Least Common Denominator Calculator:

  1. Enter your fractions, one per line (e.g., 1/2, 3/4, 5/6)
  2. The output updates instantly with the LCD and (if selected) equivalent values.

Customize the output:

Options:

  • Reduce Inputs Simplifies each fraction before calculating LCD.
  • Show Equivalent Numerators – Displays the converted numerator over the LCD.
  • Sort by Value Orders input fractions from least to greatest.

Output Modes:

  • LCD Only Just shows the least common denominator.
  • Equivalent Fractions Converts all inputs to their LCD form.
  • Step-by-Step Shows breakdown of the LCD and conversion process.

Click Copy to copy the result instantly. The display flashes to confirm output was updated.

What Least Common Denominator Calculator Can Do:

This tool is useful for homework, worksheets, and any situation where you need to bring fractions to a common base.

Fraction Conversion for Adding

Input:

1/4
2/3
5/6

Mode: Equivalent
Options: Reduce + Show Numerators ON
Output:

LCD: 12

1/4 = 3/12  
2/3 = 8/12  
5/6 = 10/12

Step-by-Step for Teaching

Input:

3/5  
2/3

Mode: Step-by-Step
Output:

Step-by-Step:
1. Input fractions: 3/5, 2/3  
2. Denominators: 5, 3  
3. Least Common Denominator: 15

3/5 → Multiply by 3 → 9/15  
2/3 → Multiply by 5 → 10/15

Quick LCD Lookup

Input:

1/8  
3/10

Mode: LCD Only
Output:
Least Common Denominator: 40

Least Common Denominator Calculator Table:

This table shows common sets of fractions and their LCD results for quick reference.

FractionsLCDEquivalents
1/2, 1/442/4, 1/4
1/3, 1/662/6, 1/6
2/3, 3/4128/12, 9/12
1/5, 2/10102/10, 2/10
3/8, 1/6249/24, 4/24
5/12, 1/82410/24, 3/24
1/6, 3/10305/30, 9/30
2/7, 4/96318/63, 28/63
1/3, 2/5155/15, 6/15
5/6, 7/103025/30, 21/30

Common Use Cases:

This calculator is perfect for:

  • Students learning to add/subtract fractions
  • Teachers building worksheets or lesson plans
  • Parents helping with homework
  • Anyone comparing or aligning different fractions

It replaces manual cross-multiplication with clean, instant output ready for copy/paste or teaching.

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