Age Calculator
Find your exact age in years, months, and days — or calculate age as of any past or future date.
How this calculator works
Enter a date of birth and this tool calculates the exact age by counting full years, months, and remaining days between two calendar dates — accounting for varying month lengths and leap years. Switch to "Age on a specific date" to find out how old someone was, or will be, on any date — useful for legal forms, eligibility checks, or just curiosity.
Frequently asked questions
How is age calculated from a date of birth?
Age is calculated by counting the number of complete years, months, and days between the date of birth and the target date (today, or any date you choose). Because months have different lengths and some years are leap years, this calculator does the day-by-day counting for you instead of relying on a simple subtraction.
Can I calculate age without knowing the exact birth date?
Yes. If you only know the birth year, the calculator shows an age range covering every possible birth date in that year. If you know the year and month, it narrows the range further. Adding the exact day gives a precise age.
Can I find out how old someone was on a past or future date?
Yes. Switch to "Age on a specific date" and enter any date — past or future. This is useful for checking eligibility cutoffs, legal age requirements, or planning ahead.
Is my birth date stored or shared anywhere?
No. All calculations run locally in your browser. The dates you enter are never sent to or stored on AuraTech's servers.
Does this calculator work for someone born on February 29 (a leap year)?
Yes. If the target year isn't a leap year, the calculator treats March 1 as the equivalent birthday for that year, then switches back to February 29 in years when it exists again.
What's the difference between my "completed age" and my "running age"?
Your completed age is the number of full years you've lived — this is what the calculator shows. Your running age is one more than that, since it counts the year you're currently living through. For example, someone who has completed 21 full years is 21 by completed age, but some people would describe themselves as "in their 22nd year." This calculator always shows completed age, which is the standard used across most of the world.
Can I figure out someone's age on a date from an old document or photo?
Yes. Switch to "Age on a specific date," enter the birth date, and set the target date to match the document or photo. This is handy for genealogy research, identifying old family photos, or making sense of a date on a historical record.
How much sleep do you need by age?
Sleep needs change throughout life. Here's the general guidance from sleep health organizations:
| Age group | Recommended sleep |
|---|---|
| Newborn (0–3 months) | 14–17 hours |
| Infant (4–11 months) | 12–16 hours |
| Toddler (1–2 years) | 11–14 hours |
| Preschool (3–5 years) | 10–13 hours |
| School age (6–12 years) | 9–12 hours |
| Teen (13–18 years) | 8–10 hours |
| Adult (18–64 years) | 7–9 hours |
| Older adult (65+ years) | 7–8 hours |