Singapore VRN Checksum Calculator
Every Singapore vehicle registration number ends in a check letter that's mathematically derived from the letters and digits before it — useful if you're checking a plate's validity, bidding for a preferred number, or just curious how the system works. Enter any prefix and number and the correct check letter appears instantly.
The check letter updates as you type — no button needed. Three-letter prefixes use only the last two letters in the calculation; numbers shorter than four digits are padded with leading zeros.
How the formula works
The last two prefix letters convert to numbers (A=1 … Z=26). Together with the four digits, the six values are multiplied by the fixed weights 9, 4, 5, 4, 3 and 2, then summed. The remainder after dividing by 19 selects the check letter from the sequence A Z Y X U T S R P M L K J H G E D C B. That's also why F, I, N, O, Q, V and W never appear as check letters on Singapore roads.
Let's make sure the retention and transfer line up smoothly with your next purchase — or if you're buying or selling a HUAT number, I can help there too.