# Code 39 Check Digit Calculator with detailed example

## Code 39 Barcode Introduction

### What is Code 39 barcode?

Barcode Code 39 is a barcode symbology that can encode uppercase letters (A through Z), digits (0 through 9) and a handful of special characters like the \$ sign. You could view the detailed Code 39 barcode introduction at What is Code 39? Code 39 barcode in detail.

## Code 39 Check Digit Calculator with example

Code 39 does not include a checksum or check digit by default. For applications requiring enhanced data security, the modulo 43 (MOD43) check character may be used as a check digit.

When a checksum or check digit is included in the Code 39 barcode, the following check character algorithm (MOD43) should be used.

### How to calculate Code 39 check digit?

1. Each data character is assigned a numerical value as shown in Table-1 below
2. Calculate the sum of the numerical values for all the data characters of a symbol
3. Divide this sum by 43.
4. The character whose value (from Table-1) is the remainder from the division in step 3) is used as the check character.

For example, calculate the check character for Code 39 data "CODE 39"

1. All 7 chars character values are 12, 24, 13, 14, 38, 3 and 9
2. Sum of the values is 113
3. Divid by 43: 113/43= 2 with remainder 27
4. Character value 27 is "R"
5. The calculated check digit is "R"
6. The complete Code 39 data with checksum is "CODE 39R"

Table-1: Code 39 numerical character values for modulo 43 check

 Character Value Character Value Character Value 0 0 F 15 U 30 1 1 G 16 V 31 2 2 H 17 W 32 3 3 I 18 X 33 4 4 J 19 Y 34 5 5 K 20 Z 35 6 6 L 21 - 36 7 7 M 22 . 37 8 8 N 23 SPACE 38 9 9 O 24 \$ 39 A 10 P 25 / 40 B 11 Q 26 + 41 C 12 R 27 % 42 D 13 S 28 E 14 T 29