Age Calculator
Calculate age from a birth date in years, months and days, with total days/weeks/months and a countdown to the next birthday.
Pick a birth date to calculate age.
About this tool
Calculate age precisely from a date of birth — in years, months and days, plus totals in days, weeks and months, and a countdown to the next birthday. It's handy for checking your own or a child's age, filling in forms, checking age-based eligibility, or planning key dates.
The tool counts real days per month and accounts for leap years, so it matches the true calendar. If you only have a Buddhist-era year, convert it first with the year converter. Everything runs in your browser — your birth date is never stored or sent anywhere.
Exact age matters more often than you'd think in Thailand: school admission cut-offs, the age floor for a driving licence (18) and for opening some accounts, insurance premiums that step up on a birthday, and official forms that ask for age in full years as of a specific date. Setting the "age as of" field to that date gives the legally correct answer instead of a rough year subtraction, which can be off by one either side of a birthday.
How to use
- 1Pick your date of birth in the date field
- 2Today's date is filled in automatically — or change it to any date
- 3See your age in years, months and days instantly
- 4See total days, weeks and months, plus a countdown to your next birthday
Frequently asked questions
- How accurate is the age calculation?
- Accurate to the day. It counts the real number of days in each month and handles leap years (Feb 29), so it matches the actual calendar.
- Can I calculate age as of a future date?
- Yes. Change the 'Age as of' field to a future date to see how old you'll be then — useful for retirement planning or age-based eligibility.
- Does it work with a Buddhist-era year?
- The date field uses the Gregorian calendar. If you only have a Buddhist-era year, subtract 543 first, or use the [year converter](/tools/year-converter).
- Is my birth date stored?
- No. Everything is calculated in your browser and nothing is sent anywhere.