Age Calculators (10)
Age CalculatorExact age in years, months, days Age Difference CalculatorGap between two people — also a tab below Birthday CalculatorNext birthday, weekday, zodiac Baby Age CalculatorAge in weeks and months How Old Will I Be CalculatorAge on any past or future date — also a tab below Chronological Age CalculatorExact age for testing Age in Months CalculatorTotal months old Age in Days CalculatorTotal days alive + milestones DOB CalculatorFind a birth date from an age — also a tab below Korean Age CalculatorInternational vs Korean ageDate Calculators (3)
Days Between Dates CalculatorCount days, weeks, months Date CalculatorAdd or subtract days, weeks, months Business Days CalculatorWorking days, weekends excludedMenu closes on outside click or Escape. All 13 Phase 1 tools are live — the homepage's 4 modes cover Age, Age at Date, Age Difference and DOB Finder as well.
Age Calculator: Find Your Exact Age in Years, Months, Days
Free online age calculator: find out exactly how old you are in years, months, days, hours and seconds from your date of birth. It runs entirely in your browser — your date of birth is never sent to a server or stored.
🧮 Age Calculator
Free • No sign-up • Private (runs in your browser)
Reference date is today — change it in Age at Date mode for a past or future date.
Save & Load Family Profiles (this browser only, no account)
Try also
What is an age calculator?
An age calculator finds your exact age from your date of birth: the completed years, months and days between your birth date and today (or any date you choose), plus totals in months, weeks, days, hours and seconds. It is used for forms, school and exam cut-offs, retirement planning, medical records and birthday milestones — anywhere an approximate age is not enough. This calculator runs entirely in your browser, needs no sign-up, and never sends your date of birth to a server.
How does the age calculator work?
It subtracts your date of birth from the reference date using exact Gregorian calendar arithmetic: completed years first, then completed months, then the days left over, using the real length of each month — never an average 30-day month. Enter your date of birth above and the result updates instantly, in all units at once.
- Enter your date of birth — pick it, or type it in DD/MM/YYYY or MM/DD/YYYY.
- Read your age in years, months and days, plus total months, weeks, days and seconds.
- Copy the result, share it as an image, or save the profile in this browser.
How to calculate age manually
Subtract birth year from current year, minus 1 if your birthday has not happened yet this year. Then count completed months from your last birthday, and the days since. Worked example: born 15 May 1990, on 14 April 2026 — 2026 − 1990 = 36, birthday not yet passed, so 35 years; from 15 May 2025 to 14 April 2026 is 10 complete months and 30 days. Final age: 35 years, 10 months, 30 days.
Leap years and February 29
Leap years follow the full Gregorian rule: a year is a leap year if divisible by 4, except century years unless divisible by 400. So 2000 was a leap year, 2100 will not be, and 2400 will be. People born on February 29 turn a year older on February 28 in non-leap years, which is the convention this calculator uses — so someone born 29 February 2000 turned 25 on 28 February 2025.
Korean and East Asian age
Traditional Korean age counts you as 1 at birth and adds a year every January 1, regardless of your birthday, so it is usually 1–2 years higher than international age. South Korea adopted international age for legal purposes in June 2023, but the traditional count is still used culturally. The result above shows your Korean age alongside your international age; see the dedicated Korean Age Calculator for the full conversion.
When you need an exact age
- Forms and documents: passports, visas and applications ask for age in years, months and days.
- School and exams: cut-off dates decide grade placement and exam eligibility to the day.
- Retirement and benefits: pension and Social Security ages depend on exact birthdays.
- Medical records: children's dosing and developmental checks use age in months and days.
- Milestones: 10,000 days, 1 billion seconds, and next-birthday countdowns.
Age in different units
The same age can be expressed in many units, and different forms ask for different ones. A 30-year-old has lived about 360 months, 1,565 weeks, 10,957 days (leap days included), about 263,000 hours and about 946 million seconds. A baby's age is usually given in weeks first, then months; a school form usually wants years and months; a test protocol wants years, months and days, sometimes written as Y;M;D. Use the totals under the result above and pick the unit the form asks for — do not convert by dividing by 30, because months are 28 to 31 days long and that shortcut drifts by days over a lifetime.
How age is counted around the world
Most of the world uses international age: you start at 0 at birth and turn a year older on each birthday. That is the system used for legal, medical and school purposes everywhere, and it is the system this calculator uses for its headline result. Traditional Korean age starts at 1 at birth and adds a year every January 1, so a baby born on 30 December is 1 at birth and 2 just two days later; South Korea retired it for legal purposes in June 2023, but it remains culturally common. Some East Asian traditions count age from the lunar new year instead. If a form, visa or test asks for your age, give the international age unless it explicitly asks for another system.
Common mistakes when calculating age
- Subtracting years only: 2026 − 1990 = 36 is wrong if the birthday has not happened yet in 2026 — the age is still 35.
- Using 30-day months: dividing total days by 30 gives a different month count across February and 31-day months.
- Ignoring leap days: a 40-year span contains about 10 leap days; skipping them undercounts age in days by 10.
- Mixing up DD/MM and MM/DD: 05/06/1990 is 5 June in most of the world and 6 May in the USA. Use the format switch above and check the result.
- Using today for a past test: a test score needs the age on the test date, not today — use Age at Date mode for that.
Frequently asked questions
How do I calculate my exact age from date of birth?
Enter your date of birth above. The calculator subtracts it from today using completed years, then months, then days, with real month lengths and leap years handled — for example, 15 May 1990 to 14 April 2026 is 35 years, 10 months, 30 days.
How old am I in years, months and days?
That is exactly what the headline result shows: completed years, then completed months since your last birthday, then remaining days. Totals in months, weeks, days and seconds are shown below it.
Does it handle leap years and Feb 29 birthdays?
Yes. It uses full Gregorian leap-year rules, and February 29 birthdays are counted as turning a year older on February 28 in non-leap years.
Is my date of birth stored?
No. All calculation runs in your browser. Family profiles are saved only in this browser's local storage, on this device, and can be deleted at any time.
How do I calculate age in Excel?
Use =DATEDIF(birth_date, TODAY(), "Y") for years, "YM" for remaining months and "MD" for remaining days. Excel's MD unit has known month-end quirks, so cross-check month-end dates here.
What is Korean age?
Traditional Korean age counts you as 1 at birth and adds a year every January 1, so it is usually 1–2 years higher than international age. South Korea adopted international age for legal purposes in June 2023, but the traditional count is still used culturally.
Written and checked against the calculator above. Last updated: 21 October 2026. Calculation: exact Gregorian calendar arithmetic, February 29 birthdays counted on February 28 in non-leap years. This tool gives calendar age only — it is not medical, legal or financial advice.