Date and time
Age & Days Since Birth Calculator
Calculate age, days since birth, the next birthday, and days remaining from a birth date and reference date.
Result
- Age
- 26years old
- Days since birth
- 9,615days
- Next birthday
- 2027-05-10
- Days until next birthday
- 246days
- Age on that day
- 27years old
Works well with
To write the same date in the Japanese era format, try the Japanese era converter.
Check age and days since birth together
Enter a birth date and reference date to see the age in full years, days since birth, the next birthday, and how many days remain until it.
Days since birth are shown as elapsed days from the birth date to the reference date, with the birth date itself treated as day 0. Age increases on each birthday, while days until the next birthday is the remaining time from the reference date.
For a date-to-date interval, use the Days Calculator. For Japanese workday deadlines, use the Business Day Calculator. If a birth date is written in a Japanese era, first convert it with the Japanese Era Converter.
Open detailed notes
Age in full years
Age in full years starts at 0 on the birth date and increases by 1 on each birthday. This is the age style commonly used for forms, identity checks, and profiles.
What the reference date means
The reference date is the date you want to calculate age for. It can be today, an application date, an exam date, or any future or past date.
How days since birth are counted
Days since birth is the elapsed time from the birth date to the reference date. This calculator treats the birth date as day 0.
Common uses
- Check the current age from a birth date.
- Check days since birth for babies, anniversaries, or personal milestones.
- Check age on a specific application date or event date.
- See how many days remain until the next birthday.
Frequently asked questions
What is the reference date used for?
It is the date you want to calculate age for. You can use today, an application date, an exam date, or any other date.
How are February 29 birthdays handled?
In non-leap years, February 28 is treated as the birthday for this calculation.
Does it show days since birth?
Yes. It shows the elapsed days from the birth date to the reference date, counting the birth date itself as day 0.
What is the difference between age, days since birth, and days until the next birthday?
Age increases on each birthday, days since birth is the elapsed number of days from the birth date, and days until the next birthday is the remaining time from the reference date.
Is my birth date saved?
No. The calculation runs locally in your browser and the input is not sent to a server.