Find out how old you will be on a certain date, or how old you were on a past one. Enter a date of birth to get the age in years, months and days, plus total months, weeks, days and hours, the weekday you were born and your next birthday.
Enter a date of birth to see the exact age in years, months and days. Leave the second date blank to calculate age as of today, or set it to any date to find age on that day.
Age is counted in completed years, months and days – the same way we normally say how old someone is. Months are calendar months, so day totals are exact while month lengths vary.
How Old Will I Be on a Certain Date?
Enter your date of birth, then type the date you care about in the second field instead of leaving it blank. Someone born on 15 June 1990 will be 39 years, 6 months and 17 days old on 1 January 2030, and exactly 50 on 15 June 2040. The same field works for past dates.
| Born 15 June 1990, age on | Exact age | Total days |
|---|---|---|
| 21 August 2026 | 36 years, 2 months, 6 days | 13,216 |
| 1 January 2030 | 39 years, 6 months, 17 days | 14,445 |
| 31 December 2035 | 45 years, 6 months, 16 days | 16,635 |
| 15 June 2040 | 50 years, 0 months, 0 days | 18,263 |
How Exact Age Is Calculated
Age is counted in completed calendar years, months and days, the same way people normally describe it. A person born on June 15 doesn’t turn a new “year” until June 15 arrives, and the months and days fill in the gap for the current partial year.
- Start from the birth date, June 15, 1990, and the target date, August 21, 2026.
- Count whole years to the last birthday, June 15, 2026: 36 years.
- Count whole months from there to August 15: 2 months.
- Count the days left to August 21: 6 days, so the age is 36 years, 2 months, 6 days.
Age on a Past Date, a Deadline or a Milestone
Any date works in the second field, past or future. That covers someone’s age at a past event, on a legal filing date, or on a birthday years from now.
How Many Months and Weeks Old Am I?
The totals answer this directly. Born on 15 June 1990, you are 434 months old on 21 August 2026, and 13,216 days, which is exactly 1,888 weeks. So the tool doubles as a how many months old am I calculator and a how many weeks old am I calculator, handy for babies and for milestone dates alike.
Day counts are popular for milestones too. 10,000 days old in years is about 27.38 years; for the same birth date it fell on 31 October 2017.
What Day of the Week Was I Born?
The result shows it alongside your age, so there’s no need for a separate what day of the week was I born calculator. It is worked out straight from the calendar: 15 June 1990, for example, was a Friday.
Need to calculate the days between two other dates instead? See our Date Calculator.
Checking Age for Forms and Eligibility
Use the rule’s own reference date, not today. Job applications, sports age groups, school entry and pensions often measure age on a fixed day.
- Check the reference date. Many rules measure age on a fixed cut-off, such as 1 September or 31 December, so enter that date as the “age on” date.
- Use completed years. Official age usually means whole years completed, so someone a day short of a birthday is still the younger age, whatever the months and days show.
- Leap-day birthdays. For people born on 29 February, the legal birthday in non-leap years varies by country, falling on either 28 February or 1 March.
The hours total assumes a midnight start, so treat it as approximate, and enter the date on your birth certificate even if you were born abroad near midnight. Counting customs also differ: the East Asian age reckoning article on Wikipedia shows why a traditional age can be a year or two higher than the one this tool gives.