Letter Series and Plate Prices: Why One Number Varies So Much
The letter series is the biggest price adjuster: the same number can differ about 3 to 10 times across series. Real examples and how to check before buying.
Published 3 October 2026
Contents
- The letter series is the biggest price adjuster
- Old two-letter series: rarity that is real
- Double-letter series and series the DLT markets specially
- A number that matches the series prefix matters more than general popularity
- Lucky word plates have their own pricing rules
- How to check the series before deciding
The letter series is the biggest price adjuster
If you compare plates with the same number in Bangkok, the biggest source of price difference is not the number but the letter series. An example from one dealer's asking price list on 29 September 2026: the single-digit new-series plate 4ขบ 1 was listed at ฿399,000, while สฎ 1, an old series, was listed at ฿3,990,000, a difference of about 10 times.
The same list as a whole shows that the series makes prices for the same number pattern differ by about 3 to 10 times. But all of these are asking prices from a single dealer on a single day, so use them to see the direction and size of the effect, not as standard prices.
| Number group | New series (baht) | Old two-letter series (baht) |
|---|---|---|
| Single digit | 179,002 to 499,004 | 1,290,000 to 3,990,000 |
| Single digit in a special prefix series | 8กก 9 at 2,250,002 and 9กฬ 9 at 2,990,002 | No data |
| Double digits | 125,000 to 220,002 | 699,000 to 3,200,002 |
| Triple digits | 250,002 to 699,002, and 9กฬ 999 at 2,490,002 | 1,190,002 to 2,690,002 |
| Four of a kind | 459,002 to 490,000 | No data |
| The number 1234 | 150,002 | 289,000 to 320,000 |
| Pairs, mirrored, alternating | 52,000 to 169,004 | 99,002 to 399,000 |
Old two-letter series: rarity that is real
Old two-letter series have the strongest effect on the Bangkok secondary market, because no more old series are being issued, so their rarity is real, not marketing. An example with the same number on the same day: ฌล 22 was listed at ฿1,290,004, while 1ขถ 22 was listed at ฿199,002. A double eight such as ญธ 88 in an old series was listed at as much as ฿3,200,002.
The caveat is that old series have little supply, so comparison samples are few as well, and old series and new series plates are different market tiers that should not be compared directly on price. This site's price calculator first compares plates in the same series. If there are not enough samples, it moves to plates with the same prefix format, such as other old two-letter series, and then to the same number across all series.
Double-letter series and series the DLT markets specially
The Department of Land Transport markets some series as special series, such as 9กก, promoted as the 'nine in front, most auspicious' series, and 3ขข, promoted as the 'precious treasure' series. The 1ขข series earned ฿61.42 million in auction revenue in September 2023, and the 2ขข series recorded a first-day high of ฿6 million in May 2024.
Series like these come from large auction rounds, so closing prices for standout numbers are much higher than in ordinary new series. For example, for the single digit in the same series, 9กก 9 closed at ฿9,620,000 and 3ขข 3 closed at ฿1,760,000. There are only 9 single-digit numbers per series, and not every number in the series reaches this price level.
A number that matches the series prefix matters more than general popularity
In the 3ขข series auction, 3333 closed at ฿4 million, but 9999 closed at ฿1,339,999 and 8888 closed at ฿1 million, even though 9999 and 8888 are generally the most popular numbers. Matching the series prefix digit therefore matters more than general popularity. This series auction had 301 numbers and earned a total of ฿45,972,643 over two days.
This observation is easy to check: see whether the series prefix digit matches the repeated digit on the plate. If it does, the plate is likely to be priced higher than other repeated numbers in the same series, and it should not be compared directly with the same number in another series.
Lucky word plates have their own pricing rules
Special plates bearing words are auctioned separately from standard series, with starting prices of ฿500,000 to ฿1,500,000. Record closing prices include รวย 9999 at about ฿18.5 million and รวย 8888 at about ฿11.1 million (2022), มังกร 999 at ฿3.73 million (July 2023), สุข 8 and อมตะ 888 at ฿2.34 million per number (December 2024), and รักคุณ 1 at ฿2.64 million (December 2025).
The price of a word plate depends on how clear its meaning is and how many people want it, not on the number alone. A word plate needs at least 2 registered bidders, otherwise the number is withdrawn from the auction. Word plates with secondary numbers therefore often close not far from the starting price, such as เจ้าสัว 44 at ฿820,000 and กำไร 999 at ฿880,000.
How to check the series before deciding
Ask four questions before comparing prices. One, is the plate an old two-letter series, a new series with a prefix digit, or a word plate? Two, is it a double-letter series or a special series marketed by the Department of Land Transport? Three, does the series prefix digit match the number on the plate? Four, do the province and vehicle type match the vehicle you will use? Two plates that give different answers to these four questions should not be compared directly on price.
This site's price calculator is free to use and always names the group it compares against. If the series is a popular one, a note is shown. When the comparison group is wider than the same series, assume the market median you see does not yet fully reflect the series premium.
Numbers mentioned in this article
FAQ on this topic
Why does the same number differ in price several times over?
Because the letter series is the biggest price adjuster. Old two-letter series are no longer issued, so they are genuinely rare, and the market also prices double-letter series and series whose prefix digit matches the plate's number highly. One dealer's asking prices show a difference of about 3 to 10 times.
What is an old series?
It means the earlier two-letter series without a prefix digit. No more old series are issued, so their number is limited and the market prices them clearly above new series. Prices depend on the popularity of the series and the number pattern.
Should I buy an old series to hold its value?
The rarity of old series is real, but liquidity is low and the buy-sell spread is wide. People who study the market conclude that plates are better bought for use and collecting than as a core investment asset, except for the top numbers in rare series. This is not investment advice.
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