Filling in an application, checking whether you qualify for something, or just curious how old you are in years and months? Here is how Thailand’s Civil and Commercial Code counts age, plus the key ages set by Thai law and government agencies.
In short
- Age counts from the day of birth (Civil and Commercial Code, section 16), in full years, full months and remaining days.
- On each birthday you are a year older.
- The age calculator does it for you, accepts Buddhist Era years, and shows days lived and days to your next birthday.
How the law counts age
Section 16: age is counted from the day of birth.
- If only the month of birth is known, the 1st of that month counts as the birthday.
- If neither day nor month is known, age counts from the first day of the calendar year of birth.
Section 193/5: periods in months or years follow the calendar and end on the day before the date matching the start. If the final month has no matching date, its last day is the end of the period.
Result: someone born on 5 March completes a year at the end of 4 March, so on 5 March they are a year older.
“Full years” (ปีบริบูรณ์) means completed years: 17 years and 11 months is not yet 18 full years.
Worked examples
| Born | On | Age |
|---|---|---|
| 5 Mar 1990 | 4 Mar 2026 | 35 years 11 months 27 days |
| 5 Mar 1990 | 5 Mar 2026 | 36 years 0 months 0 days |
| 29 Feb 2000 | 28 Feb 2026 | 25 years 11 months 30 days |
| 29 Feb 2000 | 1 Mar 2026 | 26 years 0 months 0 days |
Born on 29 February: in years without 29 February, section 193/5 makes the month’s last day, 28 February, the end of the period, so we count the new age from 1 March. That is our reading of the text; for anything legally important, ask the agency concerned or a lawyer.
To count days between two dates, such as length of service, use the days between dates calculator.
Key ages
| Age (full years) | What | Source |
|---|---|---|
| 15 | Can make a will | Civil and Commercial Code s.25 |
| 15 | Can be employed (employing children under 15 is banned) | Labour Protection Act s.44 |
| 15 | Temporary private motorcycle licence, for bikes up to 110 cc | Department of Land Transport |
| 18 | Temporary private car and motorcycle licences | Department of Land Transport |
| 18 | Right to vote (at least 18 on election day) | Constitution B.E. 2560 s.95 |
| 18 | Engagement and marriage (a court may allow earlier marriage for good reason) | Civil and Commercial Code s.1435 and s.1448 |
| 20 | Age of majority (or on marrying under s.1448) | Civil and Commercial Code s.19 and s.20 |
| 20 | Public motorcycle licence | Department of Land Transport |
| 22 | Public car and public three-wheeler licences | Department of Land Transport |
| 55 | Social Security old-age benefit, once insured status ends | Social Security Office |
| 60 | Civil servants retire at the end of the fiscal year in which they turn 60 | Government Service Gratuity and Pension Act s.19 |
| 60 | Elderly allowance begins at 600 baht a month | Department of Older Persons |
More detail
- Employees under 18: the Labour Protection Act bans overtime and holiday work (s.48) and work between 22:00 and 06:00 without written permission from the Director-General (s.47), and requires a break of at least one continuous hour after no more than four hours’ work (s.46).
- Social Security old-age benefit: with at least 180 months of contributions you get a monthly pension of 20% of your average wage over the last 60 months, plus 1.5% for every 12 months beyond 180; with fewer than 180 months you get a lump sum.
- Elderly allowance: the Department of Older Persons pays it in steps: 600 baht a month at 60–69, 700 at 70–79, 800 at 80–89 and 1,000 at 90 and over. For existing recipients, age is counted by fiscal year and the allowance doesn’t rise mid-year.
Note
This article is based on the Civil and Commercial Code as amended to No. 25 (B.E. 2568), the latest consolidated Labour Protection Act, the Constitution B.E. 2560 as published in the Royal Gazette on the Election Commission’s website, Department of Land Transport pages, the Government Service Gratuity and Pension Act, the Social Security Office website and the Department of Older Persons FAQ, read on 30 September 2026. The pension act copy we read is an older consolidation and the allowance page is undated, so check with the agency. This is general information, not legal advice.
