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calcthai.com · Thailand Road Tax Calculator
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Thailand Road Tax Calculator
Annual Thai road tax from engine size and vehicle age, including the discount for older cars and the penalty for renewing late. Free, no sign-up.
Tax on this vehicle by age
| Vehicle age | Discount | Tax payable |
|---|---|---|
| 1 years | None | 1,650.00 |
| 5 years | None | 1,650.00 |
| 6 years | 10% | 1,485.00 |
| 7 years | 20% | 1,320.00 |
| 8 years | 30% | 1,155.00 |
| 9 years | 40% | 990.00 |
| 10 years | 50% | 825.00 |
| 12 years | 50% | 825.00 |
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The AI assistant answers only questions about the calculator on this page.
Thai road tax is calculated from engine capacity, on a tiered scale, with a discount that grows as the vehicle ages. It is due annually, and the renewal sticker — the round disc displayed on the windscreen — is what shows it has been paid.
One thing worth knowing before you renew: road tax is separate from compulsory motor insurance, and you cannot renew the tax without valid insurance in place. The two are commonly confused, particularly by people used to systems where they are bundled.
How it works
The tiered rate by engine size. As with income tax, each rate applies only to the portion of engine capacity within its band.
- The first 600 cc: 0.50 baht per cc - From 601 to 1,800 cc: 1.50 baht per cc - Above 1,800 cc: 4 baht per cc
A 1,500 cc car therefore pays (600 × 0.50) + (900 × 1.50) = 300 + 1,350 = 1,650 baht.
The age discount starts in the sixth year and rises by 10 percentage points annually: 10% in year 6, 20% in year 7, 30% in year 8, 40% in year 9, and 50% from year 10 onwards. Fifty percent is the ceiling — a 20-year-old car still receives 50%, not more. That 1,500 cc car pays 825 baht once it passes ten years old.
Renewing late costs 1% of the tax per month, with any part of a month counting as a full one. That is modest in the short term, but if tax goes unpaid for more than 3 years the registration is suspended: the plates must be surrendered to the Department of Land Transport and the vehicle re-registered, which is considerably more trouble and expense.
What you need before renewing. Valid compulsory motor insurance, known as Por Ror Bor, which must be bought separately from both the tax and any comprehensive policy you hold. And if the vehicle is more than 7 years old from first registration, it needs an inspection at a licensed inspection station first.
What this tool does not cover. It calculates tax for private passenger cars of up to 7 seats, the ones with white plates and black lettering. Personal pickup trucks, which have white plates with green lettering, are taxed by vehicle weight rather than engine size. Electric vehicles are taxed by weight under their own special rates.
Frequently asked questions
What is the tax on a 1,500 cc car?
1,650 baht if the car is 5 years old or less: 300 baht for the first 600 cc at 0.50 each, plus 1,350 baht for the remaining 900 cc at 1.50 each. From ten years old the 50% discount applies, bringing it down to 825 baht.
Is tax really cheaper on an older car?
Yes. The discount begins in year 6 at 10% and rises 10 points a year to 50% in year 10, which is the maximum. A 20-year-old car still receives 50%, no more than that.
What happens if I renew late?
A penalty of 1% of the tax per month, with part of a month counted as a whole one. It is not severe in the short term, but going more than 3 years without renewing suspends the registration, requiring the plates to be surrendered and the vehicle re-registered.
What do I need before renewing?
Valid compulsory motor insurance (Por Ror Bor), bought separately from both the tax and any comprehensive policy. If the vehicle is more than 7 years old from first registration, it also needs an inspection at a licensed inspection station beforehand.
Sources
Rates last verified 25 Aug 2026