Age Calculator

Exact age down to the day — plus a few numbers that make birthdays more interesting.

Defaults to today
Age
Total days
Total weeks
Total months
Next birthday
Day of week born

How exact age is calculated

Age in "years, months, days" counts complete calendar years first, then complete months, then leftover days — the way official documents and immigration forms expect it. Because months differ in length, two people born 31 days apart can have different "months and days" readings; the total-days figure is the unambiguous one.

Where precise age actually matters

  • School cutoffs: kindergarten and sports leagues use strict "age on date X" rules.
  • Applications: visa, exam and competition eligibility often specify age on a deadline date — set the "as of" field to that date.
  • Pediatric doses & milestones: tracked in weeks and months, not years.
  • Retirement & pensions: benefits switch on at exact ages (60, 65, 67…), sometimes to the month.

Leap-day birthdays

Born February 29? Legally, most jurisdictions treat March 1 (some, February 28) as your birthday in non-leap years. This calculator counts your next birthday as the next occurrence of Feb 29 — or Mar 1 when the year has no leap day.

Ages that unlock something

AgeCommonly applies to
13Minimum age for most social media accounts (COPPA in the US)
16Learner's permit or restricted driving licence in many places
18Legal adulthood, voting, contracts in most countries
19–21Legal drinking age depending on jurisdiction
25Car rental without a young-driver surcharge; insurance rates typically drop
60–65Seniors' discounts, early pension eligibility in many systems
65–67Standard retirement and state pension age in most developed countries

These vary by country and change over time — treat them as a prompt to check your own jurisdiction rather than as legal fact. Set the "age as of" field to a specific future date to test eligibility for a deadline.

Where exact age genuinely matters

  • School enrolment. Cutoff rules are strict and usually phrased as "age on 31 December" or similar — a few days can decide a school year.
  • Sports leagues. Age brackets are typically fixed at a date in the season, not on a birthday.
  • Visa and exam eligibility. Frequently "age on the closing date" rather than on submission.
  • Infant development. Milestones and dosing are tracked in weeks and months, not years — the total-days figure is the useful one.
  • Pension timing. Claiming a state pension early or late changes the amount permanently, often by a percentage per month.

Leap-day birthdays

Born on 29 February? Most jurisdictions treat 1 March as the legal birthday in non-leap years, though a few use 28 February. This calculator counts your next birthday as the next actual 29 February when one exists, and 1 March otherwise. Your true anniversary count is unaffected — you simply gain a genuine birthday once every four years.

Frequently asked questions

Why does my age in months not equal years × 12?
It does, plus the extra complete months since your last birthday. "Total months" counts every complete month since birth: a person exactly 20½ years old shows 246 total months.
Can I calculate age at a past or future date?
Yes — change the "age as of" field. Useful for "how old was I when…" and for eligibility deadlines.
Does it handle time zones?
Dates are interpreted in your device's local time zone. Around midnight or across hemispheres, a birth certificate's local date is the authoritative one.
Why do some cultures count age differently?
Traditional East Asian age reckoning counted a newborn as one year old and added a year at new year rather than on the birthday, which could make someone "two" days after birth. South Korea used this system alongside international age until standardising on international reckoning in 2023. This calculator uses international age — years actually completed since birth.
Can I work out someone's birth year from their age?
Roughly, but not exactly — a 30-year-old today was born either 30 or 31 years ago depending on whether their birthday has passed this year. If you need precision, use the "age as of" field with a known date where you also know the age, which narrows it to a specific twelve-month window.
What's my age in dog years?
The "multiply by seven" rule is a myth. Dogs mature very quickly at first — a one-year-old dog is roughly equivalent to a 15-year-old human, and a two-year-old to about 24 — after which each year adds roughly four to five human-equivalent years, varying considerably by breed size.