Age Calculator
Calculate exact age in years, months, weeks, days, hours, and minutes from any date of birth — or how old you will be on any future date.
What is an age calculator?
An age calculator works out the exact time between a date of birth and any other date — today by default — and expresses it as years, months and days, plus total months, weeks, days, hours and minutes, and the number of days until the next birthday. Enter the two dates above and every figure updates at once.
It answers the questions that come up on forms and at milestones: how old you are to the day for a passport, visa or school enrolment; how old you were when something happened; how old you will be on a future date; and exactly when you cross the ages that matter for driving, drinking, voting, retirement accounts and Social Security.
How age is counted
Your age is the number of completed years since birth: you are 29 until the moment of your 30th birthday. The calculator counts full years first, then full months within the current year, then the remaining days — the same way you would do it by hand. If your birthday is February 29, most U.S. legal rules treat March 1 as the anniversary in non-leap years, and the calculator does the same.
Total days are the exact count between the two dates, so a 26-year-old born on January 1, 2000 has lived 9,755 days as of September 16, 2026 — that is 1,393 weeks, or about 234,000 hours.
U.S. age milestones
| Age | What changes |
|---|---|
| 16 | Driver's licence in most states (with graduated restrictions); can work most non-hazardous jobs |
| 18 | Legal adult: vote, sign contracts, marry without consent, serve on a jury, enlist; men must register with Selective Service |
| 21 | Buy alcohol and tobacco; gamble in most casinos; rent a car (with a young-driver fee under 25) |
| 25 | Rent a car without surcharges; car-insurance rates typically fall; eligible for the U.S. House of Representatives |
| 26 | Aged off a parent's health insurance plan (end of the month you turn 26 under most plans) |
| 50 | Catch-up contributions allowed in 401(k) and IRA accounts |
| 55 | Penalty-free 401(k) withdrawals if you leave that employer in or after the year you turn 55 (the "rule of 55") |
| 59½ | Penalty-free withdrawals from IRAs and 401(k)s |
| 62 | Earliest age to claim Social Security retirement benefits, permanently reduced by about 30% versus full retirement age |
| 65 | Medicare eligibility (enrolment window opens three months before) |
| 67 | Social Security full retirement age for anyone born in 1960 or later |
| 70 | Social Security benefit stops growing — the latest sensible age to claim |
| 73 | Required minimum distributions (RMDs) from traditional IRAs and 401(k)s begin (rising to 75 for people born in 1960 or later) |
Round-number birthdays you did not know you had
| Milestone | Happens at about |
|---|---|
| 1,000 days old | 2 years 9 months |
| 1,000 weeks old | 19 years 2 months |
| 10,000 days old | 27 years 5 months |
| 500 months old | 41 years 8 months |
| 20,000 days old | 54 years 9 months |
| 30,000 days old | 82 years 2 months |
Set the second date to a future day to find out exactly when you hit one of these — or when a child turns 18, when a lease ends, or how old you will be at retirement.
Formula
Age in years, months and days is found by subtracting the date of birth from the target date component by component, borrowing when a component goes negative — exactly as you would subtract dates by hand:
- Days = target day − birth day. If negative, borrow one month and add the number of days in the month before the target month.
- Months = target month − birth month (minus any borrowed month). If negative, borrow one year and add 12.
- Years = target year − birth year (minus any borrowed year).
The totals use the exact elapsed time: total days = (target date − birth date) counted on the calendar, which automatically includes leap days; weeks = days ÷ 7; hours = days × 24; minutes = hours × 60. Total months = years × 12 + months.
Worked example
Someone born on January 1, 2000, on September 16, 2026:
- Years: 2026 − 2000 = 26; months: 9 − 1 = 8; days: 16 − 1 = 15 → 26 years, 8 months, 15 days
- Total months: 26 × 12 + 8 = 320
- Total days: 9,755 (including 7 leap days: 2000, 2004, 2008, 2012, 2016, 2020, 2024)
- Total weeks: 9,755 ÷ 7 = 1,393
- Next birthday: January 1, 2027 — 107 days away, when they turn 27
A case that needs borrowing — born March 25, 1990, checked on September 16, 2026: days 16 − 25 is negative, so borrow a month (August has 31 days): 16 + 31 − 25 = 22 days, months 9 − 3 − 1 = 5, years 36 → 36 years, 5 months, 22 days.
How to use this calculator
- Enter the date of birth (or any start date).
- Leave the second date as today, or change it to any past or future date.
- Read the exact age in years, months and days, plus the totals and the countdown to the next birthday.
The first date must be on or before the second; the calculator shows nothing until it is. Times of day are ignored — ages are counted in whole calendar days.
Other things you can do with two dates
- Age at an event — set the second date to the event date: how old you were when you graduated, or how old a parent was when you were born.
- Age on a future date — set the second date to a retirement date, a wedding, or the start of a school year to check eligibility cut-offs.
- Age difference between two people — run each person's date of birth against the same date and subtract.
- Pet age — works for any birth date; for the human-equivalent, see the dog age and cat age calculators.
Related tools
- Date difference calculator — days, weeks and months between any two dates
- Days until calculator — countdown to any date
- Add or subtract days from a date
- Retirement calculator — will your savings last from your chosen retirement age?
Frequently asked questions
Does the calculator handle leap years?
Yes. Total days are counted on the real calendar, so every February 29 between the two dates is included — someone born in 2000 has lived through seven leap days by 2026. For a February 29 birthday, the next-birthday countdown uses March 1 in years that have no February 29, matching how most U.S. agencies treat "leaplings".
Can I find my age on a past or future date?
Yes — change the second date. Set it to a past date to see how old you were then, or a future date to see how old you will be. This is the easiest way to check whether a child meets a school-entry cut-off, when you become eligible for Medicare, or your age at a planned retirement date.
At what age can I start drawing Social Security?
You can claim retirement benefits from age 62, but the monthly amount is permanently reduced — by about 30% for people born in 1960 or later, whose full retirement age is 67. Waiting past full retirement age adds about 8% a year until 70, after which there is no further increase. The right age depends on health, other income and whether a spouse will rely on survivor benefits.
When am I penalty-free from my 401(k) or IRA?
From age 59½ for both. Withdrawals before that generally cost a 10% penalty on top of income tax, with exceptions — including the "rule of 55", which allows penalty-free 401(k) withdrawals from an employer you leave in or after the year you turn 55, and Roth IRA contributions (not earnings), which can be withdrawn at any age.
How many days old am I?
Enter your date of birth and read the "total days" line. A quick estimate is your age in years × 365.25: a 30-year-old has lived roughly 10,958 days. You pass 10,000 days at about 27 years and 5 months, and 20,000 days at 54 years and 9 months.
Why does my age in months not match years × 12?
It does, plus the extra months since your last birthday: 26 years and 8 months is 26 × 12 + 8 = 320 months. If you were expecting a different number, check whether the second date is set to today — the calculator uses whatever date is in that box.
How is age calculated for someone born on February 29?
The calculator treats February 29 birthdays as falling on March 1 in years without a leap day, so a leapling turns 21 on March 1 in a common year — which is how most U.S. states handle drinking age and other legal thresholds. In leap years the real birthday is used.