CalcThai
calcthai.com · Age Calculator
General & conversion
Age Calculator
Exact age in years, months and days, plus days lived and the next birthday. Accepts Thai Buddhist years, and shows when you reach each Thai legal age.
Years you reach each legal milestone
| Milestone | Year reached | Status |
|---|---|---|
| Age 15 — minimum working age, can join social security Section 33 | 2,005 | Reached |
| Age 18 — the right to vote, and a car driving licence | 2,008 | Reached |
| Age 20 — full legal majority under the Civil and Commercial Code | 2,010 | Reached |
| Age 55 — can claim the social security old-age benefit | 2,045 | 19 years away |
| Age 60 — normal retirement, eligible for the old-age allowance | 2,050 | 24 years away |
Ask about this page
The AI assistant answers only questions about the calculator on this page.
Working out an age is not simply this year minus the year of birth — if the birthday has not come round yet this year, that gives an answer one year too high. This calculator works to the day, taking the day, month and year into account, and shows which year you reach each legally significant age in Thailand.
It also handles the Thai Buddhist Era, which is what you will meet on Thai official documents. Enter either year format and the tool works out which you meant.
How it works
The correct method. Subtract the year of birth from the current year, then check whether the birthday has already passed this year. If it has not, subtract one more.
For example, someone born in December 1990, calculating in August 2026: 2026 − 1990 = 36, but their actual age is 35, because December has not arrived yet.
Thai Buddhist Era years. Thailand uses the Buddhist Era, which runs 543 years ahead of the Gregorian calendar. The year 2026 CE is 2569 BE. Every Thai official document — identity cards, contracts, government forms — uses BE, so being able to convert quickly is genuinely useful if you live here. This tool accepts either: a year of 2400 or above is treated as BE, anything lower as CE.
Legally significant ages in Thailand:
- 15 — the minimum working age, and the age at which you can be enrolled in social security under Section 33 - 18 — the voting age under section 95 of the 2017 Constitution, and eligible for a car driving licence - 20 — full legal majority under section 19 of the Civil and Commercial Code. This is not the voting age, which is 18 - 55 — able to claim the social security old-age benefit, provided insured status has ended. With 180 months or more of contributions this is a monthly pension for life; with fewer, a lump sum - 60 — normal retirement age, and the point at which the state old-age allowance begins
People born on 29 February in a year without that date are generally treated as ageing on 1 March.
Frequently asked questions
How do I convert a Thai Buddhist year to a Gregorian one?
Subtract 543. A Thai document showing 2569 BE means 2026 CE. Going the other way, add 543. This calculator accepts either format — anything from 2400 upwards is read as a Buddhist year.
Why is my age one year less than year minus year of birth?
Because your birthday has not happened yet this year. Someone born in December 1990 is 35 in August 2026, not 36, even though 2026 − 1990 = 36. The extra year only arrives on the birthday itself.
What ages matter legally in Thailand?
15 is the minimum working age and the point of eligibility for social security under Section 33. 18 is the voting age and allows a car driving licence. 20 is full legal majority under the Civil and Commercial Code, which is a separate threshold. 55 allows a claim on the social security old-age benefit once insured status ends. 60 is normal retirement and the start of the state old-age allowance.
What about people born on 29 February?
In years without that date, they are generally treated as ageing on 1 March.
Sources
Rates last verified 25 Aug 2026