Age Calculator by Date of Birth
Find your exact age in years, months, days, hours, and minutes instantly. Calculate age between any two dates — including the day of the week you were born and your next birthday countdown.
Age Calculator
Enter your date of birth to calculate your exact age
Enter your date of birth or the birth date you want to calculate age for
Leave as today’s date, or choose a specific date to calculate age at that point in time
Choose your preferred output format
Your Age Result
Exact age with full breakdown
Enter your date of birth and click Calculate My Age to see your exact age in years, months, days, hours, and minutes — plus your next birthday countdown.
Simple, Accurate Age Calculation
Our calculator uses calendar-precise arithmetic — accounting for leap years, varying month lengths, and time zones — to give you the most accurate result possible.
Enter Date of Birth
Type in any date of birth. The calculator accepts any date from 1 January 1900 onwards, including leap year birthdays like 29 February.
Choose Your End Date
By default we use today’s date, but you can pick any past or future date to calculate how old someone was or will be at a specific moment.
Get the Full Breakdown
See your age in years, months, days, total weeks, hours, and minutes — plus the day of the week you were born and your next birthday countdown.
Leap Years Handled
Leap year birthdays (29 February) are automatically handled. In non-leap years, the calculator uses 28 February or 1 March depending on convention.
Age in Different Units
How age translates across common units of time for reference.
| Age | Total Days (approx.) | Total Weeks (approx.) | Total Hours (approx.) | Milestone |
|---|---|---|---|---|
| 1 year old | 365 days | 52 weeks | 8,760 hrs | First birthday 🎂 |
| 10 years old | 3,652 days | 521 weeks | 87,648 hrs | Decade milestone |
| 18 years old | 6,574 days | 939 weeks | 157,766 hrs | Legal adult (UK/US) |
| 21 years old | 7,670 days | 1,095 weeks | 184,086 hrs | Legal adult (many countries) |
| 30 years old | 10,957 days | 1,565 weeks | 262,980 hrs | 30th birthday |
| 40 years old | 14,610 days | 2,087 weeks | 350,640 hrs | 40th birthday |
| 50 years old | 18,262 days | 2,608 weeks | 438,288 hrs | Golden jubilee |
| 60 years old | 21,915 days | 3,130 weeks | 525,960 hrs | Diamond jubilee |
| 100 years old | 36,524 days | 5,217 weeks | 876,576 hrs | Centenarian 🎖️ |
Age Calculator FAQ
Answers to the most common questions about calculating age by date of birth.
To calculate your exact age, subtract your date of birth from today’s date. Count the full years first, then the remaining months, then the remaining days. For example, if you were born on 15 March 1990 and today is 26 June 2026, you are 36 years, 3 months, and 11 days old. Our calculator does this automatically and also shows your age in total days, hours, weeks, and minutes.
To find how many days old you are, our calculator counts every calendar day from your date of birth to today, including leap days. For example, a person who turned 30 years old on a standard date is approximately 10,957 days old. The exact figure depends on how many leap years have occurred during your lifetime. Enter your date of birth above to get your precise total.
A leap year has 366 days (an extra 29 February) and occurs every 4 years, except century years not divisible by 400. If you were born on 29 February, you technically only have a birthday every 4 years. For age calculation in non-leap years, most countries legally recognise 28 February as the birthday. Our calculator follows this convention automatically and flags leap-year birthdays in the results.
Yes — simply toggle off “Always use today’s date” and enter any custom end date in the As of Date field. This lets you calculate how old someone was at a historical event, how old they will be at a future date, or the time elapsed between any two dates. Our calculator handles any valid date range.
Our age calculator displays the day of the week for your date of birth automatically in the results. For example, 1 January 2000 was a Saturday. The calculation uses the Gregorian calendar and the Tomohiko Sakamoto algorithm to determine the exact weekday for any date since 1 AD.
The next birthday countdown shows how many days, hours, and minutes remain until your next birthday. If your birthday has already passed this year, it counts down to the same date next year. For 29 February birthdays, it counts down to the next 29 February (the next leap year). The countdown is calculated from the current moment including hours and minutes for precision.
Our age calculator is 100% accurate to the calendar day. It accounts for all leap years between your date of birth and the end date, variable month lengths (28, 29, 30, or 31 days), and correctly handles edge cases like birthdays on the last day of the month. The total hours and minutes calculation assumes 24 hours per day and does not account for daylight saving time differences.
Most Western countries use the Gregorian calendar method: you turn a year older on your birthday each year, starting from 0 at birth. The traditional East Asian age system (used in Korea, China, and Japan historically) counts age differently — everyone is considered 1 at birth and gains a year on 1 January each year rather than on their actual birthday. Our calculator uses the standard Western (Gregorian) method.