Age Calculator
Your precise age in years, months, and days — plus total days alive and the countdown to your next birthday.
Calculate your exact age
How exact age is calculated
Counting age sounds trivial until you try to program it. "Years, months, days" requires borrowing, the same way long subtraction does: if the day-of-month hasn't arrived yet, you borrow days from the previous month; if the birth month hasn't arrived, you borrow a year. Because months have different lengths and leap years add a day, two people born one day apart can briefly differ by what looks like a whole month. This calculator handles the borrowing precisely, using the actual lengths of the actual months involved.
Worked example
Born June 15, 1990, calculating on June 10, 2026: the birthday hasn't arrived yet, so the answer is 35 years, 11 months, 26 days — not 36. Total days lived is the straight difference between the dates: about 13,144 days, leap days included automatically. Five days later, the odometer rolls over to 36 years, 0 months, 0 days.
Where exact age actually matters
Beyond curiosity, precise age computations show up in real paperwork: eligibility cutoffs for school enrollment and sports leagues, retirement and Social Security milestones (where months matter to the benefit amount), insurance rating, immigration forms, and medical dosing for infants, where age is tracked in weeks and days. "Days alive" is also just satisfying to know — your 10,000th day lands a few months past your 27th birthday, and your 20,000th in your mid-fifties.
Leap years and edge cases
A leap year adds February 29 roughly every four years (century years only if divisible by 400 — 2000 was a leap year, 1900 wasn't). People born on February 29 typically celebrate on February 28 or March 1 in common years, but their legal age still advances normally: laws count years elapsed, not calendar matches. This calculator uses real calendar arithmetic, so leap days are counted exactly once each.
Frequently asked questions
How many days old am I?
Enter your date of birth and today's date — the calculator shows total days lived, counting leap days exactly. Rough mental math: years × 365.25.
Why does the months part of my age look odd around month ends?
Because months have different lengths, 'one month after January 31' is ambiguous. The calculator borrows days from the actual previous month, the standard convention, so results near month boundaries can shift by a day or two versus other methods.
Can I calculate age at a date in the past or future?
Yes — set the 'Age on date' field to any date after the birth date: a historical date, a deadline, or a future birthday.
How does the next-birthday countdown handle February 29?
If the next calendar year has no February 29, the countdown targets March 1, the most common legal convention. Leap-day birthdays still get an exact count in leap years.
Is my 'real' age different in other systems?
Some cultures historically counted everyone as one year old at birth and added years at New Year (notably the traditional Korean system, officially retired in 2023). This calculator uses international age — time actually elapsed since birth.
How age is calculated — more complex than it seems
Calculating exact age requires handling calendar irregularities that make simple subtraction unreliable. The complications: leap years (February has 28 or 29 days), months of different lengths (28–31 days), and the convention of whether a birthday is "complete" on the birth date or the day after. The standard approach: count complete years, then complete months within the final partial year, then remaining days. A person born January 15, 2000 is 25 years, 6 months, and some days old in late July 2025 — the specific day count depends on the exact calculation date and how partial months are handled.
The age displayed in this calculator represents the age "completed" — the number of full years, months, and days that have elapsed since the birth date. This matches how legal age is typically defined (you are "21" starting on your 21st birthday) and how medical age is recorded (age at last birthday).
Age calculations in real-world contexts
Legal and financial contexts: Minimum ages in Nevada: 21 for alcohol purchase and casino gambling, 18 for tobacco purchase, 16 for driving, 18 for voting and most contracts. Social Security: early benefits available at 62, full retirement age 67 for most current workers, maximum benefits at 70. Medicare eligibility: 65. IRA required minimum distributions: 73 (as of 2023 SECURE 2.0 Act). Roth IRA 5-year rule and qualified distribution age: 59½.
Medical contexts: Pediatric dosing guidelines use exact age in months for infants and toddlers. Screening recommendations are age-triggered: mammogram guidelines start at 40 or 45 depending on the organization, colonoscopy at 45, prostate screening discussions at 50. Geriatric medicine defines "young old" (65–74), "middle old" (75–84), and "oldest old" (85+) as clinically distinct categories.
Real estate and mortgage contexts: FHA loans have no minimum age beyond legal contract age (18). Reverse mortgages require all borrowers on title to be 62+. Age does not affect conventional mortgage qualification, though income trajectory and remaining earning years affect underwriting judgment on very long loan terms relative to retirement age.
Frequently asked questions
How do I calculate how many days old I am?
Multiply your complete years by 365, add days for each leap year in that span, add days for each complete month in the current partial year (using the actual number of days in each month), and add the remaining days. For most purposes, an online date calculator is more practical than doing this by hand — the accumulated leap year corrections require knowing which years were divisible by 4, 100, and 400.
What age is considered a senior in Nevada?
Legal definitions vary by context. Social Security considers 62 the earliest retirement eligibility and 67 the full retirement age for most current workers. Medicare eligibility is 65. Many businesses offer "senior discounts" starting at 60 or 65. The AARP defines membership eligibility at 50. Nevada Senior Services programs generally serve residents 60+. There is no single universal definition.
Does my age affect my mortgage eligibility?
Age discrimination in mortgage lending is prohibited under the Equal Credit Opportunity Act (ECOA). Lenders cannot deny a mortgage or offer worse terms based on age alone. However, income and employment status — which often correlate with retirement age — are legitimate underwriting factors. A 70-year-old with strong pension income and Social Security will qualify for a mortgage on the same terms as a 40-year-old with similar income and credit. Reverse mortgages are age-restricted (62+ for all borrowers on title) and work inversely — the lender pays the homeowner.
What is chronological vs. biological age?
Chronological age is the number of years since birth — what this calculator measures. Biological age is an estimate of how "aged" your body actually is based on biomarkers: telomere length, DNA methylation patterns, cardiovascular fitness, inflammatory markers, and metabolic health. Biological age can be significantly younger or older than chronological age — lifestyle factors including exercise, diet, sleep, and stress management strongly influence it. Biological age tests are available through specialized labs but are not yet standardized enough for clinical diagnostic use.
Disclaimer: Age calculations are based on the dates you input. This calculator is for general informational purposes. Legal age determinations for specific purposes (driving, voting, benefits eligibility) are governed by applicable law and should be confirmed with relevant authorities.