GCD Function in Excel: Greatest Common Divisor

GCD Function in Excel: Greatest Common Divisor featured illustration

📎 This article includes 1 downloadable practice file ↓

⏱ 2 min readUpdated 5 October 2026

MathLevel: IntermediateAvailable in: Excel 2007+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. GCD in practice
  5. Where you will use it
  6. Worked example
  7. Mistakes people make
  8. Related functions
  9. Continue learning

GCD returns the largest number that divides all inputs — for simplifying ratios and finding pack sizes.

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Syntax

=GCD(number1, [number2], ...)
Argument What it means
number1… Whole numbers.

Examples

Example 1

=A2/GCD(A2,B2)&":"&B2/GCD(A2,B2)

Turns 1920 and 1080 into the ratio 16:9.

GCD in practice

Where you will use it

  • Simplify ratios like 1920:1080
  • Biggest equal pack size for two quantities
  • Teaching fractions

Worked example

ABFormulaResult
19201080=GCD(A2,B2)120
4836=GCD(A3,B3)12
175=GCD(A4,B4)1

Results calculated in Excel.

Mistakes people make

MistakeWhat to do instead
DecimalsInputs are truncated to integers
RatiosDivide both by GCD: A/GCD & ":" & B/GCD

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📎 Practice files for this article

  • 📗
    Practice workbook: Math & rounding24 tasks on realistic sales data — type your formula, the Check column turns green when it is right. Answers sheet included.
    ⬇ XLSX · 35 KB

Free to use for learning. Files with macros (.bas) are plain text — import them with Alt+F11 → File → Import File, and always test on a copy.

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