Code 39 Checksum Calculator

How Code 39 Checksum Calculator Works?

The Code 39 Checksum Calculator works by adding the Code 39 values of all data characters, dividing the sum by 43, and appending the character whose value equals the remainder. The Modulus 43 check character is optional in the Code 39 specification.

1. 1Convert each character to its Code 39 value: 0–9 = 0–9, A–Z = 10–35, then - . space $ / + % = 36–42.
2. 2Add all values.
3. 3Compute the remainder of the sum divided by 43.
4. 4Look up the character with that value and append it before the stop character (*).

Code 39 Checksum Calculator Formula

The Code 39 checksum formula is Check = C39[(Σ v(cᵢ)) mod 43].

S = Σ v(cᵢ)
Check character = C39[S mod 43]

• v(c) is the Code 39 value 0–42.
• C39 is the 43-character Code 39 set.

C(12) + O(24) + D(13) + E(14) + 3(3) + 9(9)
Sum = 75
75 mod 43 = 32 → 'W'
Encoded data = *CODE39W*

Code 39 Checksum Calculator Conversion Table

The Code 39 conversion table maps the 7 special characters to their values next to sample data and check characters.

What is Code 39 Checksum Calculator?

A Code 39 Checksum Calculator is a tool that computes the optional Modulus 43 check character of a Code 39 barcode. Code 39 encodes 43 characters and was developed in 1974 by Intermec.

The Health Industry Bar Code (HIBC) standard requires the Modulus 43 check character on every HIBC Code 39 label.

What are the uses of Code 39 Checksum Calculator?

There are 4 main uses of the Code 39 Checksum Calculator, including HIBC labels, asset tags, and industrial part labels.

• HIBC labels: Medical device suppliers add the mandatory Mod 43 character.
• Asset tags: Companies add the check character to Code 39 asset tags to cut misreads.
• Industrial part labels: Factories protect part numbers on shop-floor labels.
• Scanner setup: Technicians test scanners with check-character verification on.