Home › UK Calculators › Age Calculator
Age calculator
Free · runs in your browser · updated 2026-07-05
How to use the age calculator
- Enter the date of birthUse the date picker or type it.
- Optionally change the 'as of' dateDefaults to today — change it to calculate age at any date.
- Read the breakdownExact age, total days, and countdown to the next birthday.
Frequently asked questions
How is exact age calculated?
Count full years since birth, then full months since the last birthday, then remaining days. This is the same convention used for legal age — you turn a new age at 00:00 on your birthday.
How many days old am I?
The tool shows total days lived — a 30-year-old has lived roughly 10,957 days, since each year averages 365.25 days.
What age is used for official purposes in the UK?
Completed years. You're 17 until the day of your 18th birthday, regardless of months and days — which is what the years figure here shows.
Can I calculate age at a past or future date?
Yes — change the 'as of' date to any date, useful for forms asking your age on a specific date, like school admissions or policy start dates.
Related tools
Three percentage calculators in one: find X% of a number, work out what percentage one number is of another, and calculate percentage increase or decrease..
BMI CalculatorCalculate your BMI from height and weight in metric or imperial units, and see where you sit against NHS healthy weight categories..
Holiday Entitlement CalculatorWork out statutory UK holiday entitlement (5.6 weeks) for full-time, part-time and mid-year starters, in days — including pro-rata calculations..