What this calculator does
How old am I sounds like it should have a one-number answer, but the honest answer is a breakdown: years, months and days, since "36" on its own drops the months and days that have passed since the most recent birthday. Enter a date of birth and this calculator gives the full figure, worked out to today by default.
Alongside the exact age, it shows the total number of days and weeks lived so far, and a countdown to the next birthday, which is usually the second thing people want once the headline age is settled.
The formula
Whole years are counted from the date of birth to the reference date. The remaining months and days are then counted forward from the most recent birthday, so the figure reads as a genuine years, months and days breakdown rather than a rounded estimate.
| Term | Meaning |
|---|---|
| Date of birth | The date the age is measured from. |
| As of this date | The date the age is calculated up to, defaulting to today. |
| Next birthday | The coming occurrence of the birth month and day, in the current or following year, whichever has not yet arrived. |
The inputs explained
| Field | What to enter |
|---|---|
| Date of birth | The date of birth to calculate the age from. |
| As of this date | The date to calculate the age as of, normally left on today. |
When to use it
Working out your exact age right now
Leaving the "as of" date on today gives a live answer to how old am I, down to the month and day, rather than just the number of full years.
Checking how old you were, or will be, on a specific date
Changing the "as of" date to a past or future date answers how old you were on a particular occasion, or how old you will be by a coming date such as the start of a course or a new job.
Counting down to a birthday
The next birthday figure gives a straightforward day count to the coming birthday, which is worked out alongside the current age rather than needing a separate calculation.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How age in years, months and days changes for people born a decade apart, checked today
A range of birth years, all checked as of today, to show how the breakdown compares across ages.
| Date of birth | You are | Total days lived |
|---|---|---|
| 1960 | 66 years, 1 months, 29 days old | 24,165 |
| 1970 | 56 years, 1 months, 29 days old | 20,513 |
| 1980 | 46 years, 1 months, 29 days old | 16,860 |
| 1990 | 36 years, 1 months, 29 days old | 13,208 |
| 2000 | 26 years, 1 months, 29 days old | 9,555 |
| 2010 | 16 years, 1 months, 29 days old | 5,903 |
Questions
How old am I if I was born in 1989?
Enter 1989 and the month and day you were born in the date of birth field, leave the "as of" date on today, and the exact age in years, months and days is worked out immediately, along with the day of the week you were born on.
Why does this show months and days as well as years?
A single year figure hides how close you are to the next birthday. The full years, months and days breakdown is the more precise and genuinely useful answer to how old am I, especially close to a birthday.
What is the difference between this and the age calculator?
This page is built around the plain "how old am I" question and its everyday framing. The fuller age calculator covers the same maths with more detail, including age expressed in total weeks and hours.
Can I check how old I was on a date in the past?
Yes. Set "As of this date" to any past date on or after the date of birth, and the age shown will be the age as of that day rather than today.
For the same calculation with more detail, including total hours lived, see the age calculator. To count down to a birthday, or any other date, precisely, use the countdown calculator.