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Age Calculator

Calculate your exact age in years, months, and days. Find out how many days until your next birthday, or how old you'll be on any future date.

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What is Age Calculator?

An age calculator computes the exact difference between a birth date and today — or any target date — in years, months, and days. Edge cases make this more complex than simple subtraction: leap year birthdays (February 29 exists only in leap years — most countries use February 28 as the legal birthday in non-leap years), the Korean age system (where a person is born at age 1 and everyone gains a year on January 1 rather than on their individual birthday), and legal age milestones that vary by country (18 for voting and contracts in most countries, 21 for alcohol in the United States, 65 for full Social Security retirement in the US, 67 in the UK). The birthday countdown feature shows exact days remaining for planning celebrations and tracking legal transitions.

How to use

  1. Enter your birth date using the date picker or by typing in the day, month, and year.
  2. Optionally enter a target date to calculate age at a specific point in time — defaults to today if left blank.
  3. Read your exact age displayed in years, months, and days.
  4. Check the days-until-next-birthday countdown for celebration planning.
  5. Use the future age feature to find out how old you will be on any future date.

Why it matters

Exact age matters in many legal and medical contexts. School enrollment cutoffs use precise age-on-a-specific-date rules that vary by district and country, determining whether a child enters a grade a full year ahead or behind peers. Pediatric medical dosing for children under two years old uses age in months, not years — a 16-month-old and a 23-month-old receive different doses. Insurance premium brackets, Social Security benefit eligibility, and pension calculations all reference specific age thresholds where being a few days short can shift benefit start dates or trigger different rate tiers.

Pro tip

For retirement planning, calculate your exact age on January 1 of each target year. Social Security and many pension systems use age-in-year rules — your benefit amount or eligibility tier is determined by your age on a specific date within the calendar year. Being three days short of a qualifying age cutoff can shift your benefit start date by months or trigger a lower benefit calculation tier, a difference worth knowing well in advance.

Frequently Asked Questions

Your exact age is the difference between your date of birth and today, broken down into years, months, and days. This calculator uses precise date arithmetic to account for leap years and months of different lengths.
Enter your date of birth and the calculator will automatically show how many days remain until your next birthday. If today is your birthday, a special message will appear.
Use the 'How old will I be on...' section. Enter any future date and the calculator will tell you exactly how old you will be on that date, in years.
Yes — this calculator uses precise date arithmetic that correctly handles leap years, February 29 birthdays, and months with different numbers of days.
If you were born in 1990, you are currently 35–36 years old depending on your exact birth month and today's date. Enter your full birth date above for a precise result.