How the checksum letter works
Every Singapore vehicle licence plate is a prefix of one to three letters, a number from 1 to 9999 and a checksum letter, like SBA 1234 G. The last letter isn’t part of the series: it’s worked out from the rest, so a mistyped or misread plate shows up.
- Take the last two letters of the prefix (SBA → BA) and turn them into numbers, A = 1 to Z = 26. A one-letter prefix counts as 0 then that letter (E → 0, 5).
- Write the number as four digits, with leading zeros: 23 → 0, 0, 2, 3.
- Multiply the six figures by 9, 4, 5, 4, 3, 2 in turn, and add them up.
- Divide the total by 19: the remainder picks the letter from the table below.
| Remainder | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 |
|---|
| Letter | A | Z | Y | X | U | T | S | R | P | M | L | K | J | H | G | E | D | C | B |
So F, I, N, O, Q, V and W are never checksum letters. Some worked examples: SBS 9889 U, E 23 H, SG 2017 C.
A plate’s checksum catches any one wrong digit: no digit’s weight times a change of 1 to 9 is a multiple of 19. See also Wikipedia: Vehicle registration plates of Singapore.
Questions
Why does a Singapore car plate end in a letter?
The last letter is a checksum: it’s worked out from the prefix letters and the number, so a plate that has been mistyped or misread usually doesn’t add up. It catches any one wrong digit.
Can you tell how old a car is from its plate?
Roughly. Car series run in order, EA in 1972 up to SBA in 1984 and on through the S series, and each new one comes out every month or two. A car with an SMP plate was registered in July 2019 or later. But numbers can be bid for after the series opens, or kept from an older car, so the car may be newer than its series. The dates come from LTA’s list of car prefixes.
What’s the latest car plate series?
The latest car series is SPN, first open for bidding in October 2026, after SPM (September 2026) and SPL (July 2026). A new one comes out every month or two, in order through the alphabet, though LTA skips some: the third letter is never I or O, and there was no SPF. The dates are from LTA’s list of car prefixes (checked 2 Nov 2026) and, for SPN, LTA’s circular; every series is in one CSV.
How do I bid for a car plate number?
When LTA opens a new series, its numbers go up for bidding on OneMotoring: the least you can bid is S$1,000 with GST, one bid can name up to three numbers of the same prefix in order of preference, and a number you win can’t be transferred to someone else. LTA announces each bidding in a circular with its dates. The checksum letter comes with the number, so type it here to see what your plate will end in.
What do the other prefixes mean?
SH is a taxi, F a motorcycle, G a light goods vehicle, Y a heavy one, X a very heavy one or a prime mover, P a private bus, W engineering plant, SG a public bus and QX an emergency vehicle. The checker tells you when you type one. (Wikipedia)
Which letters are never used as the checksum?
F, I, N, O, Q, V and W: with 19 possible remainders, only 19 letters are needed.
Does it work for motorcycles, taxis, buses and goods vehicles?
Yes: every series of plates uses the same checksum. Only special government vehicles and event vehicles have plates without one.