# Vehicle Checksum Formula

A vehicle checksum is the last alphabet of a vehicle license plate. It is derived from the following formula.

Prefix | |
---|---|

SG | 11 – (5 × 1st No.) – (4 × 2nd No.) – (3 × 3rd No.) – (2 × 4th No.) |

SBS | 2 – (5 × 1st No.) – (4 × 2nd No.) – (3 × 3rd No.) – (2 × 4th No.) |

SMB | 9 – (5 × 1st No.) – (4 × 2nd No.) – (3 × 3rd No.) – (2 × 4th No.) |

TIB | 7 – (5 × 1st No.) – (4 × 2nd No.) – (3 × 3rd No.) – (2 × 4th No.) |

### Suffix Table

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 0 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|

A | B | C | D | E | G | H | J | K | L | M | P | R | S | T | U | X | Y | Z |

**Note:**Letters F, I, N, O, Q, V & W are omitted.

### Example

For example, the registration plate of **SG5999**.

Using the above formula for **SG**-prefixed plates, you should get a statement like this: *11–(5× 5)–(4×9)–(3×9)–(2×9)*. A quick input of the statement on Google should give a result of

**-95**.

Using the result, mod the number with **19**, you will get a number from 0 to 18. You can mod the number by 19 using Google. For the above example where the result is **-95**, type *-95 mod 19* into the Google search bar and it would calculate the answer, **0**.

Compare the answer against the table above for the suffix.

Hence the checksum for **SG5999** is **Z**.

*Alternatively, you may use this checksum calculator tool to find the suffix.*

### How "Mod 19" works

Mod 19 works in a way that the number `19`

is deducted from a number until the remainder reaches 18 or less.

For example, if you get a result of `-95`

from the given formula.

- Remove the minus sign (modulus)
- Deduct
`19`

from`95`

as many times as you can before remainder reaches 18 or less`95 - 19 - 19 - 19 - 19 - 19 = 0`

- Substitute remainder
`0`

with the letter Z and it will be the suffix of the license plate