Engineering

BIN2DEC Function in Excel

Converts a binary number to decimal.

Syntax

  • =BIN2DEC(number)

Arguments

  • number (required): Binary number (up to 10 characters)

Examples

  • =BIN2DEC(1100100) - Convert binary to decimal - Result: 100

BIN2DEC in technical sheets

  • Document units in adjacent cells — many engineering functions require exact unit strings.
  • Use [CONVERT](/functions/convert/) for unit changes before specialized formulas.
  • Validate inputs with [ISNUMBER](/functions/isnumber/) and range checks.

Common errors

  • #NUM! if not valid binary
  • Max 10 digits

Use cases

  • Number conversion
  • Programming
  • Data processing

Frequently asked questions

  • How do I convert binary IP addresses to decimal? Split the binary IP into octets and convert each: =BIN2DEC("11000000")&"."&BIN2DEC("10101000")&"."&BIN2DEC("00000001")&"."&BIN2DEC("00000001") converts binary to 192.168.1.1.
  • Why does BIN2DEC return #NUM! error? BIN2DEC only accepts valid binary (0s and 1s only) up to 10 digits. Check for invalid characters (2-9) or numbers that are too long. The 10-digit limit means max value is 1111111111 (511 or -512 for negative).
  • How do I handle negative binary numbers? BIN2DEC uses two's complement for 10-digit numbers. If the first digit is 1 and there are 10 digits, it's negative. 1111111111 = -1, 1111111110 = -2. Shorter numbers are always positive.

Editorial review

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