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Age Calculator

How old am I? Enter your date of birth to instantly calculate your exact age in years, months, and days, plus total days lived and a countdown to your next birthday. Free, no sign-up.

How Age Is Calculated

Age is the length of time elapsed between a date of birth and a reference date, expressed in whole years, months, and days rather than a single rounded number. This calculator finds your age by subtracting your date of birth from today's date, accounting for month length and leap years to give a precise breakdown.

For example, if you were born on March 15, 1990 and today is March 18, 2026, your exact age is 36 years, 0 months, and 3 days, not simply 36.

Years

Full years since birth. Increases on your birthday each year.

Months

Remaining full months after counting full years. Resets to 0 on your birthday.

Days

Remaining days after counting full years and months. Accounts for varying month lengths.

Leap Years and February 29 Birthdays

Leap years (divisible by 4, with century exceptions) add an extra day, February 29, every 4 years. The calculator handles all leap years automatically. If you were born on February 29, your birthday is treated as March 1 in non-leap years for the "next birthday" countdown.

How the Next Birthday Countdown Works

The countdown builds a birthday date for the current year using your birth month and day, then compares it against today. If that date has already passed (or is today), the calculator moves it forward one year and counts the days from today until that future date.

This is why the countdown always shows a number between 0 and 366, never a negative value: as soon as one birthday passes, the calculator immediately starts counting toward the next one rather than showing days since the last birthday.

Common Use Cases

Legal eligibility checks: Quickly confirm exact age for voting, driving, drinking, marriage, or employment age requirements that depend on a precise birth date rather than a rounded figure.
Forms and applications: Many job, visa, insurance, and school enrollment forms ask for age in years and months as of a specific date. This calculator gives that breakdown instantly instead of manual subtraction.
Retirement and pension planning: Pension eligibility, Social Security, and superannuation access ages are usually defined in exact years and months, so knowing your precise age helps confirm when you qualify.
Pediatric and medical reference: Growth charts, vaccination schedules, and some medication dosing charts are indexed by age in months or days for infants and young children.
Milestone and countdown tracking: The total days lived figure and next-birthday countdown are popular for birthday planning, anniversary tracking, and personal milestone celebrations (10,000 days old, for example).

Chronological Age vs. Corrected Age

The result above is chronological age: time elapsed since the actual date of birth. For infants born prematurely, pediatricians often track a second figure called corrected (or adjusted) age, which subtracts the number of weeks born early from the chronological age, per American Academy of Pediatrics guidance. This gives a fairer basis for comparing growth and developmental milestones against full-term peers, and is typically used until around age 2. This calculator reports chronological age only; for corrected age tracking, follow your pediatrician's guidance.

Accuracy Notes

Local date and time: The calculator reads today's date from your device's local clock, not a server. If you are checking your age right around midnight, results are based on your browser's local calendar day, which can differ from UTC.

Total days vs. calendar age: Total days lived is a raw count of 24-hour periods since birth, while the years/months/days breakdown follows the calendar (so a 1-year-old is not necessarily exactly 365 days old, since leap years can add a day).

Frequently Asked Questions

How do I calculate my exact age?▾
Enter your date of birth in the field above. The calculator instantly shows your age in years, months, and days as of today. The calculation accounts for leap years and varying month lengths.
How is age calculated in years, months, and days?▾
The calculator subtracts your birth date from today. It borrows days from the previous month when needed (accounting for month length) and borrows months from the current year when the month difference is negative. This gives you a precise breakdown rather than just rounding to whole years.
How many days have I been alive?▾
The "Total days lived" stat shows the exact number of calendar days from your date of birth to today, including leap days. The result updates automatically when you enter your birth date.
How are leap years handled?▾
Leap years are handled automatically. The total days count uses JavaScript's Date object which accounts for all historical and future leap years. If your birthday is February 29, the next birthday is calculated as March 1 in non-leap years.
Does this tool store my date of birth?▾
No. The calculation runs entirely in your browser. Your date of birth is never sent to any server, stored, or logged anywhere.
Can I calculate someone else's age?▾
Yes, just enter their date of birth. The calculator works for any person born in the past. There is no restriction on the birth year.
What is the "days until next birthday" count?▾
This shows how many calendar days remain from today until your next birthday. If today is your birthday, it shows Today! The next birthday is always calculated in the upcoming year.
Can I calculate age as of a past or future date instead of today?▾
This calculator always compares your date of birth against today's date. To find age as of a different date, apply the same method manually: subtract the birth date from the target date, borrowing days and months the same way, or use the total days figure as a starting point and adjust.
What is corrected (adjusted) age for premature babies?▾
Chronological age is time since birth. Corrected age subtracts the number of weeks a baby was born early from their chronological age, and pediatricians commonly use it instead of chronological age when tracking growth and developmental milestones for infants born preterm, typically until around 2 years old. This calculator reports chronological age only; ask your pediatrician for corrected age guidance specific to your child.

By Toolember · Updated September 2026