Math & Trig

LCM Function in Excel

Returns the least common multiple.

Syntax

  • =LCM(number1, [number2], ...)

Arguments

  • number1 (required): First number
  • number2 (optional): Additional numbers

Examples

  • =LCM(4, 6) - LCM of 4 and 6 - Result: 12

LCM in reporting workflows

  • Use absolute references when copying formulas across rows.
  • For conditional totals see [SUMIF](/functions/sumif/) and [SUMIFS](/functions/sumifs/).
  • Filtered lists may need [SUBTOTAL](/functions/subtotal/) instead of SUM on visible cells only.

Common errors

  • #NUM! if any number < 0

Use cases

  • Scheduling
  • Fraction operations
  • Mathematics

Frequently asked questions

  • What is LCM in Excel? LCM finds the Least Common Multiple - the smallest number that is a multiple of all given numbers. LCM(4,6)=12 because 12 is the smallest number divisible by both 4 and 6.
  • How do I use LCM for scheduling? LCM helps find when events coincide. If Task A runs every 4 days and Task B every 6 days, =LCM(4,6)=12 means they'll coincide every 12 days. For three cycles: =LCM(4,6,8)=24 days.
  • How do I add fractions with different denominators using LCM? Find LCM of denominators for common denominator. For 1/4 + 1/6: LCM(4,6)=12. Convert: 3/12 + 2/12 = 5/12. Formula: =(A1*(LCM(B1,D1)/B1) + C1*(LCM(B1,D1)/D1)) / LCM(B1,D1).

Editorial review

  • Reviewed by Excel.Directory Editorial Team. Updated May 2026.

When to use LCM

  • Scheduling — common Math & Trig scenario for LCM.
  • Fraction operations — common Math & Trig scenario for LCM.
  • Mathematics — common Math & Trig scenario for LCM.

LCM in the Math & Trig category

  • Browse all Math & Trig functions at /categories/math-trig/ for related formulas.
  • LCM syntax: =LCM(number1, [number2], ...)
  • number1 (required): First number
  • number2 (optional): Additional numbers
  • Confirm LCM arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.

Formula checklist before you copy down

  • Confirm LCM arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.
  • If results look wrong, check for text stored as numbers and invisible spaces with TRIM.
  • Spot-check three known input rows manually against expected output.

Related Excel functions

  • GCD (/functions/gcd/): Returns the greatest common divisor.
  • MOD (/functions/mod/): Returns the remainder after a number is divided by a divisor.

Errors to watch for

  • #NUM! if any number < 0 — review causes on linked error pages in the directory.

Copy-paste audit workflow

  • Enter LCM on three test rows with known expected output documented on a QA tab.
  • Fill down only after absolute references are locked on lookup tables and rate tables.
  • Compare against manual calculation or a calculator for financial and statistical functions.
  • Search this directory for comparison guides when choosing between similar functions in the same category.

LCM worked examples to copy

  • =LCM(4, 6) — LCM of 4 and 6. Expected result: 12.

LCM reference summary for crawlers and offline review

  • LCM belongs to the Math & Trig category in Excel. Returns the least common multiple.
  • Full syntax: =LCM(number1, [number2], ...). Open /functions/lcm/ for parameters, FAQs, and related pages.
  • Common mistakes: #NUM! if any number < 0
  • Pair this function with comparison guides when another Excel formula might fit the same task better.
  • Review fix-excel-formula-errors when unexpected errors appear after upgrading Excel or sharing across locales.