Age calculators
Work out an exact age from a date of birth, the gap between two ages, a child's age for testing or a premature baby's corrected age, a dog or cat's age in human years, your generation, and your retirement age in the US or UK.
Which age calculator do I need?
- How old am I, or how old was someone on a given date: the age calculator gives years, months and days, how many days old you are, and the days to your next birthday.
- The gap between two people's ages: the age difference calculator.
- A child's age for a test or assessment: the chronological age calculator sets it out in years, months and days the way test manuals ask.
- A baby who was born early: the corrected age calculator counts from the due date.
- A pet's age in human years: the dog age calculator works by size, and the cat age calculator adds the life stage.
- Which generation you belong to: what generation am I, by birth year.
- When you can retire on a state pension: the retirement age calculator for US Social Security and the UK State Pension.
How ages are counted
In everyday use an age is the number of whole years since birth. You turn a year older on your birthday, so someone born in 2000 is 25 before their birthday in 2026 and 26 after it. The months and days are what is left over since the last birthday or monthly date.
Months have different lengths, which is why calculators sometimes disagree by a day near the end of a month. Each calculator here says how it handles a birth date such as the 31st or February 29 in a month that does not have that day.
For a plain count of days between two dates, without birthdays, use days between two dates.
Common questions
Is my date of birth sent anywhere?
No. Every calculator here works in your browser, and nothing you type leaves your device.
Are pet ages exact?
No. Dogs and cats age at different rates depending on size, breed and health, so human years are an estimate for comparison. Your vet is the best guide to your own pet.