Plate Number

Partial plate (e.g. SBA1234) → computes check letter.
Full plate (e.g. SBA1234G) → validates it.
Use * for unknown letters, # for unknown digits → e.g. SBA###A or S**123A.

Algorithm

Up to two prefix letters (A = 1 … Z = 26) plus four zero-padded digits are each multiplied by a fixed weight, summed, then taken mod 19. For a three-letter prefix only the last two letters are used.

Position L1L2 D1D2 D3D4
Weight 945432

Single-letter prefix → L1 = 0.  Letters F I N O Q V W are never check letters.

Check letter map (remainder 0 – 18)

Prefix Reference

LTA assigns certain prefixes exclusively to specific vehicle classes, organisations, or government use. Some series are deliberately skipped and no plates are ever issued for them.