Code 128 barcode specification
Example:
Code 128 is one of the more complex linear barcodes, with a greater capacity than Code 25 or Code 39, but requiring better quality images for reliable recognition.
Key features:
- 4 different width of bar/space.
- 3 symbol sets (A, B and C).
- Symbol set C encodes pairs of digits and is one of the best ways to store large numbers in a linear barcode.
- Ability to switch between symbol sets.
- Barcodes include start and stop character plus a built in checksum.
- Each character is made up of 3 bars and 3 spaces – except for the stop character which has 4 bars and 3 spaces.
- The number of black bars should leave remainder 1 when divided by 3.
A Code 128 barcode is written as follows:
Start character (start A, start B or start C) (3 bars)
1 or more data characters (3 bars each)
Checksum character – calculated from the data characters (3 bars)
Stop character (4 bars)
Specification:
| value | A | B | C | Pattern |
|---|---|---|---|---|
| 0 | SPACE | SPACE | 00 | 2 1 2 2 2 2 |
| 1 | ! | ! | 01 | 2 2 2 1 2 2 |
| 2 | “ | “ | 02 | 2 2 2 2 2 1 |
| 3 | # | # | 03 | 1 2 1 2 2 3 |
| 4 | $ | $ | 04 | 1 2 1 3 2 2 |
| 5 | % | % | 05 | 1 3 1 2 2 2 |
| 6 | & | & | 06 | 1 2 2 2 1 3 |
| 7 | ‘ | ‘ | 07 | 1 2 2 3 1 2 |
| 8 | ( | ( | 08 | 1 3 2 2 1 2 |
| 9 | ) | ) | 09 | 2 2 1 2 1 3 |
| 10 | * | * | 10 | 2 2 1 3 1 2 |
| 11 | + | + | 11 | 2 3 1 2 1 2 |
| 12 | , | , | 12 | 1 1 2 2 3 2 |
| 13 | – | – | 13 | 1 2 2 1 3 2 |
| 14 | . | . | 14 | 1 2 2 2 3 1 |
| 15 | / | / | 15 | 1 1 3 2 2 2 |
| 16 | 0 | 0 | 16 | 1 2 3 1 2 2 |
| 17 | 1 | 1 | 17 | 1 2 3 2 2 1 |
| 18 | 2 | 2 | 18 | 2 2 3 2 1 1 |
| 19 | 3 | 3 | 19 | 2 2 1 1 3 2 |
| 20 | 4 | 4 | 20 | 2 2 1 2 3 1 |
| 21 | 5 | 5 | 21 | 2 1 3 2 1 2 |
| 22 | 6 | 6 | 22 | 2 2 3 1 1 2 |
| 23 | 7 | 7 | 23 | 3 1 2 1 3 1 |
| 24 | 8 | 8 | 24 | 3 1 1 2 2 2 |
| 25 | 9 | 9 | 25 | 3 2 1 1 2 2 |
| 26 | : | : | 26 | 3 2 1 2 2 1 |
| 27 | ; | ; | 27 | 3 1 2 2 1 2 |
| 28 | < | < | 28 | 3 2 2 1 1 2 |
| 29 | = | = | 29 | 3 2 2 2 1 1 |
| 30 | > | > | 30 | 2 1 2 1 2 3 |
| 31 | ? | ? | 31 | 2 1 2 3 2 1 |
| 32 | @ | @ | 32 | 2 3 2 1 2 1 |
| 33 | A | A | 33 | 1 1 1 3 2 3 |
| 34 | B | B | 34 | 1 3 1 1 2 3 |
| 35 | C | C | 35 | 1 3 1 3 2 1 |
| 36 | D | D | 36 | 1 1 2 3 1 3 |
| 37 | E | E | 37 | 1 3 2 1 1 3 |
| 38 | F | F | 38 | 1 3 2 3 1 1 |
| 39 | G | G | 39 | 2 1 1 3 1 3 |
| 40 | H | H | 40 | 2 3 1 1 1 3 |
| 41 | I | I | 41 | 2 3 1 3 1 1 |
| 42 | J | J | 42 | 1 1 2 1 3 3 |
| 43 | K | K | 43 | 1 1 2 3 3 1 |
| 44 | L | L | 44 | 1 3 2 1 3 1 |
| 45 | M | M | 45 | 1 1 3 1 2 3 |
| 46 | N | N | 46 | 1 1 3 3 2 1 |
| 47 | O | O | 47 | 1 3 3 1 2 1 |
| 48 | P | P | 48 | 3 1 3 1 2 1 |
| 49 | Q | Q | 49 | 2 1 1 3 3 1 |
| 50 | R | R | 50 | 2 3 1 1 3 1 |
| 51 | S | S | 51 | 2 1 3 1 1 3 |
| 52 | T | T | 52 | 2 1 3 3 1 1 |
| 53 | U | U | 53 | 2 1 3 1 3 1 |
| 54 | V | V | 54 | 3 1 1 1 2 3 |
| 55 | W | W | 55 | 3 1 1 3 2 1 |
| 56 | X | X | 56 | 3 3 1 1 2 1 |
| 57 | Y | Y | 57 | 3 1 2 1 1 3 |
| 58 | Z | Z | 58 | 3 1 2 3 1 1 |
| 59 | [ | [ | 59 | 3 3 2 1 1 1 |
| 60 | \ | \ | 60 | 3 1 4 1 1 1 |
| 61 | ] | ] | 61 | 2 2 1 4 1 1 |
| 62 | ^ | ^ | 62 | 4 3 1 1 1 1 |
| 63 | _ | _ | 63 | 1 1 1 2 2 4 |
| 64 | NUL | ` | 64 | 1 1 1 4 2 2 |
| 65 | SOH | a | 65 | 1 2 1 1 2 4 |
| 66 | STX | b | 66 | 1 2 1 4 2 1 |
| 67 | ETX | c | 67 | 1 4 1 1 2 2 |
| 68 | EOT | d | 68 | 1 4 1 2 2 1 |
| 69 | ENQ | e | 69 | 1 1 2 2 1 4 |
| 70 | ACK | f | 70 | 1 1 2 4 1 2 |
| 71 | BEL | g | 71 | 1 2 2 1 1 4 |
| 72 | BS | h | 72 | 1 2 2 4 1 1 |
| 73 | HT | i | 73 | 1 4 2 1 1 2 |
| 74 | LF | j | 74 | 1 4 2 2 1 1 |
| 75 | VT | k | 75 | 2 4 1 2 1 1 |
| 76 | FF | I | 76 | 2 2 1 1 1 4 |
| 77 | CR | m | 77 | 4 1 3 1 1 1 |
| 78 | SO | n | 78 | 2 4 1 1 1 2 |
| 79 | SI | o | 79 | 1 3 4 1 1 1 |
| 80 | DLE | p | 80 | 1 1 1 2 4 2 |
| 81 | DC1 | q | 81 | 1 2 1 1 4 2 |
| 82 | DC2 | r | 82 | 1 2 1 2 4 1 |
| 83 | DC3 | s | 83 | 1 1 4 2 1 2 |
| 84 | DC4 | t | 84 | 1 2 4 1 1 2 |
| 85 | NAK | u | 85 | 1 2 4 2 1 1 |
| 86 | SYN | v | 86 | 4 1 1 2 1 2 |
| 87 | ETB | w | 87 | 4 2 1 1 1 2 |
| 88 | CAN | x | 88 | 4 2 1 2 1 1 |
| 89 | EM | y | 89 | 2 1 2 1 4 1 |
| 90 | SUB | z | 90 | 2 1 4 1 2 1 |
| 91 | ESC | { | 91 | 4 1 2 1 2 1 |
| 92 | FS | | | 92 | 1 1 1 1 4 3 |
| 93 | GS | } | 93 | 1 1 1 3 4 1 |
| 94 | RS | ~ | 94 | 1 3 1 1 4 1 |
| 95 | US | DEL | 95 | 1 1 4 1 1 3 |
| 96 | FNC 3 | FNC 3 | 96 | 1 1 4 3 1 1 |
| 97 | FNC 2 | FNC 2 | 97 | 4 1 1 1 1 3 |
| 98 | SHIFT B | SHIFT A | 98 | 4 1 1 3 1 1 |
| 99 | CODE C | CODE C | 99 | 1 1 3 1 4 1 |
| 100 | CODE B | FNC 4 | CODE B | 1 1 4 1 3 1 |
| 101 | FNC 4 | CODE A | CODE A | 3 1 1 1 4 1 |
| 102 | FNC 1 | FNC 1 | FNC 1 | 4 1 1 1 3 1 |
| 103 | start A | start A | start A | 2 1 1 4 1 2 |
| 104 | start B | start B | start B | 2 1 1 2 1 4 |
| 105 | start C | start C | start C | 2 1 1 2 3 2 |
| 106 | stop | stop | stop | 2 3 3 1 1 1 2 |
Note:
The CODE A, B and C symbols latch all following characters to the specified symbol set where as SHIFT A and SHIFT B just change the interpretation of the next character.
Checksum Calculation:
The checksum is calculated as follows:
- Multiply the value of each character by it’s position in the barcode (indexed from 1).
- Add up all the results from step 1.
- Add on the value of the start character.
- The checksum is remainder on division by 103.
For example, if you are encoding the string ABCD1234 in symbol set A then the checksum values will be:
Steps 1 and 2:
(33 * 1) + (34 * 2) + (35 * 3) + (36 * 4) + (17 * 5) + (18 * 6) + (19 * 7) + (20 * 8) = 836
Step 3:
836 + 103 = 939
Step 4:
939 mod 103 = 12
So the checksum character should have value 12.
