How the age is worked out
The calculator counts whole years, then whole calendar months, then the days left over – the same way people normally say an age. Because months have different lengths, “1 month” can be 28 to 31 days; the remaining days are counted from the last monthly date.
Worked example: born 15 May 1990, on 13 November 2026.
- 15 May 1990 → 15 May 2026 = 36 years
- 15 May 2026 → 15 October 2026 = 5 months
- 15 October → 13 November = 29 days
- Age: 36 years, 5 months, 29 days – 13,331 days in total.
Born on 29 February?
In years without a 29 February, the calculator counts the birthday on 28 February. For some legal purposes in the UK a person born on 29 February reaches a new age on 1 March in a non-leap year, so check if it matters (for example for a licence or a pension).
Uses
- Filling in forms that ask for age in years and months (school, sports, nurseries).
- Checking an age on a past or future date – for example an age at a travel date or on a deadline.
- Fun facts: your age in days or weeks, and the weekday you were born.
Need the number of days between any two dates instead? Use the date difference calculator.
Ages that matter in the UK
- 16: you can apply for a provisional driving licence (to ride a moped) and leave school in some parts of the UK after the summer term.
- 17: you can drive a car once you have a provisional licence.
- 18: you can vote in UK general elections and buy alcohol.
- State Pension age is set by law and depends on your date of birth – check the official State Pension age tool on GOV.UK.
The calculator gives the exact age on any date, which helps with forms that ask “age at” a particular date, such as an age on 31 August for school years.
All the maths uses the calendar date only, so time zones and clock changes never move the answer by a day.