How the age calculator works
This age calculator from birthday computes the exact difference between your date of birth and today (or any target date). It counts full calendar years, then remaining months, then remaining days, the same way age is expressed in everyday life.
It also converts your age into total months, total weeks, total days, and total hours, answering questions like how old am I, "how old am I in days" or "how many months old am I" instantly.
Tip: Use the "Calculate age as of" option to find your age at any past or future date, useful for age verification, milestone tracking, or calculating age differences between two people.
Chronological age explained
Chronological age is the amount of time that has elapsed since a person's birth, measured by the calendar. It's the standard way age is determined worldwide for legal, medical, and social purposes. To get it in years, months, and days on any date, the way school, psychological, and sports-eligibility forms ask for it, use the chronological age calculator.
Chronological age
Based on your date of birth. Fixed and objective. Used for legal and official purposes. This is what the calculator computes.
Biological age
Based on health biomarkers (telomere length, epigenetic clocks). Can be younger or older than chronological age. Estimated by medical tests, not calendars.
Age in different units
Here's roughly what age 30 looks like in other units, using the average Gregorian year of 365.2425 days (the exact count depends on how many February 29ths fall in those years). Use the age in days calculator above for your exact numbers:
| Unit | Age 30 ≈ |
|---|---|
| Years | 30 |
| Months | 360 |
| Weeks | 1,565 |
| Days | 10,957 |
| Hours | 262,968 |
Weeks to months converter
Need to know how many months a certain number of weeks is? A Gregorian month averages 4.348 weeks (365.2425 days a year ÷ 12 ÷ 7), so divide the weeks by 4.348. Common conversions: 26 weeks in months is about 6.0 months. 21 weeks to months is about 4.8 months.
| Weeks | ≈ Months |
|---|---|
| 12 weeks | 2.8 months |
| 16 weeks | 3.7 months |
| 20 weeks | 4.6 months |
| 21 weeks | 4.8 months |
| 24 weeks | 5.5 months |
| 26 weeks | 6.0 months |
| 30 weeks | 6.9 months |
| 36 weeks | 8.3 months |
| 40 weeks | 9.2 months |
Formula: months = weeks ÷ 4.348 (average weeks per Gregorian month).
How old am I if I was born in...?
Quick reference for common birth years (as of 2026). To calculate birth year from age, subtract your age from 2026. For exact age including months and days, use the calculator above.
| Birth Year | Age in 2026 |
|---|---|
| 2010 | 16 years old |
| 2008 | 18 years old (turns 18) |
| 2006 | 20 years old |
| 2005 | 21 years old (turns 21) |
| 2004 | 22 years old |
| 2000 | 26 years old |
| 1995 | 31 years old |
| 1990 | 36 years old |
| 1985 | 41 years old |
| 1980 | 46 years old |
| 1975 | 51 years old |
| 1970 | 56 years old |
For example, if you were born in 2006, you are 20 years old in 2026 (2026 minus 2006 = 20). Your exact age depends on whether your birthday has already passed this year, so use the calculator above for precision.
Leap year handling
A leap year occurs every 4 years (with exceptions for century years not divisible by 400), adding February 29 to the calendar. This calculator handles leap years automatically:
- Total days count includes all leap days within your lifetime
- If you were born on Feb 29, your age in years increments on March 1 in non-leap years
- The next birthday countdown uses Feb 29 in leap years and Mar 1 otherwise
- The same rule covers any birth date on the 29th, 30th or 31st: in a month too short to have that day, the month is counted as complete on the 1st of the next month (born Jan 31, you are 0 months 28 days old on Feb 28 of a common year, and 1 month old on Mar 1). There is no official US rule for this; it is the convention this calculator uses.
Age calculation for legal purposes
Age thresholds are set by whichever law or program you are dealing with. A few federal ones, with the agency that sets each:
| Age | Milestone |
|---|---|
| 18 | Voting: 18 on or before Election Day (USA.gov) |
| 62 | Earliest Social Security retirement benefits, permanently reduced (SSA) |
| 65 | Medicare: the 7-month initial enrollment period runs from 3 months before to 3 months after the birthday month (Medicare.gov) |
| 67 | Full Social Security retirement age for anyone born in 1960 or later (SSA) |
| 73 | Required minimum distributions from IRAs and workplace plans start in the year you reach this age (IRS) |
Driving, drinking, contract and criminal-court ages are set by state law and differ by state; check your state's rules.
FAQs
How is age calculated?
Count the complete years, then the complete months, then the leftover days between the birth date and the date you care about. A year only counts once the same month and day come round again: someone born March 15, 1994 is 32 on March 15, 2026 but still 31 on March 14, 2026.
Does the calculator account for leap years?
Yes. It works from real calendar dates, so every February 29 in your lifetime is in the day count. For a February 29 birthday it treats March 1 as the birthday in common years: born February 29, 2000, you were 25 on March 1, 2025. When a birth date is the 29th, 30th or 31st and a month is too short to have that day, the month is counted as complete on the 1st of the next month.
How do I calculate my age in months?
Take whole years times 12 and add the extra months. At 25 years and 7 months that is (25 × 12) + 7 = 307 months. The Total Months box above does this for you.
How do I calculate my age in days?
It depends on how many leap days your life has spanned, so count the actual calendar days, which is what the Total Days box does. As a rough check, multiply years by 365.2425, the average length of a Gregorian year: 30 years comes to about 10,957 days.
What is the legal age in the United States?
It depends on what for. Voters must be 18 on or before Election Day (USA.gov). Medicare's initial sign-up window opens three months before a person turns 65 (Medicare.gov). Social Security retirement benefits can start at 62, and full retirement age is 67 for anyone born in 1960 or later (SSA). Required minimum distributions from retirement accounts start in the year a person reaches 73 (IRS). Driving, drinking and contract ages are set by state and federal law for each purpose; check the agency that governs the one you need.
How old am I if I was born in 1995?
In 2026, for example, you are 30 before your birthday and 31 after it; add one for each year after that. With a June 15, 1995 birthday, you turn 31 on June 15, 2026. Put your full birth date in the calculator for the exact years, months and days.
How to calculate age between two dates?
Open 'Calculate age as of a different date' and pick the second date instead of today. The result is the gap between the birth date and that date, whether it is in the past or the future, so it works for an age at a past event or on a future deadline.
What is age verification?
It means confirming someone's age before a sale or service with an age limit, usually by checking a government-issued ID. A date of birth typed into a website is only a claim. This page can work out an exact age from a birth date, but it verifies nothing about who entered it.
Is age calculated from date of birth or date of conception?
From the date of birth. Legal, school and medical records in the United States count age from the day a person was born, and this calculator does the same.
How do I calculate birth year from age?
Take the current year minus your age, then take away one more if this year's birthday is still ahead. For example, at 30 in 2026: 2026 − 30 = 1996 if the birthday has passed, 1995 if it hasn't.
Can I calculate a conception date from a due date?
Only roughly. A due date is set 266 days after the assumed conception date (280 days from the last period, less 14), so counting back 266 days from a December 1, 2026 due date gives about March 10. Cycles vary, so treat it as an estimate.
What is the full retirement age for Social Security?
It depends on birth year, per the Social Security Administration's schedule: 66 and 6 months for 1957, 66 and 8 months for 1958, 66 and 10 months for 1959, and 67 for 1960 or later. Benefits can begin as early as 62 at a permanent reduction. The age is federal, so it is the same in every state.