How Many Weeks Old Am I? The 4,000 Weeks Idea, Explained With Real Numbers
Your age in weeks is your age in years multiplied by 52.1775, plus the weeks since your last birthday. A 30-year-old is about 1,565 weeks old; a 40-year-old about 2,087; and the often-quoted lifetime figure of 4,000 weeks works out to a little under 77 years.
This article covers the arithmetic, where the 4,000 weeks number comes from, why people find weeks a more useful unit than days or years, and how to keep the number in view without it becoming a chore.
The arithmetic
A Gregorian year averages 365.2425 days, and 365.2425 divided by 7 is 52.1775 weeks. So:
- Multiply your age in whole years by 52.1775.
- Count the days since your last birthday and divide by 7.
- Add the two.
Someone who turned 34 exactly 60 days ago: 34 x 52.1775 = 1,774.0, plus 60 / 7 = 8.6, giving about 1,782.6 weeks. For a rounder answer, count the exact days since birth using the method in how old am I in days and divide by 7.
Useful landmarks, using the same conversion:
| Weeks | Age |
|---|---|
| 1,000 | 19 years, 2 months |
| 1,500 | 28 years, 9 months |
| 2,000 | 38 years, 4 months |
| 2,500 | 47 years, 11 months |
| 3,000 | 57 years, 6 months |
| 3,500 | 67 years, 1 month |
| 4,000 | 76 years, 8 months |
Your thousandth week arrives a couple of months after your 19th birthday, and each further thousand takes about 19 years and 2 months.
Where “4,000 weeks” comes from
Four thousand weeks is 76.7 years, which is close to average life expectancy in many wealthier countries, and it is a round number. That combination made it a popular shorthand well before Oliver Burkeman’s 2021 book “Four Thousand Weeks” put it on a cover. It is not a prediction for any individual, and life expectancy at birth is not the same as the expected remaining years for someone who has already reached adulthood, which is usually higher. Treat 4,000 as a frame for thinking, not a deadline.
Why weeks, rather than days or years
Each unit tells you something different:
- Years move too slowly to notice. Thirty-four is the same number for twelve months.
- Days are too many to feel. Twelve thousand of anything is an abstraction.
- Weeks land in between. A few thousand is a quantity you can picture, and one week is a period you have a real sense of. That is why the “life in weeks” grid, a chart of 52 columns by around 80 rows with the lived weeks filled in, has become a standard way of drawing a lifetime. You can take it in at a glance and you can find this week on it.
A grid also makes the shape of a life visible: childhood is a thin band at the top, working years a wide middle, and the unfilled space below is what remains. Whether that is motivating or uncomfortable depends on the person, which is discussed in memento mori for your phone.
Making the number, or the grid
The lowest-effort option is a spreadsheet: put a birth date in one cell, use a today() function in another, subtract, and divide by 7. Several free templates exist for the full grid and they all do the same thing.
If you want it on a wall, a printed poster of the grid with a pen is the original version, and it has one advantage over any app: filling in a box by hand on Sunday is a small weekly ritual that an automatic counter cannot give you.
If you want it on your phone, there are dedicated life-in-weeks apps that draw the grid as a widget or wallpaper, and there are age counters that show a single number. The age counter comparison describes the categories and what to check before installing any of them.
Choosing between a grid and a number
A grid answers “where am I in the whole?” A single number answers “how much has passed?” They suit different temperaments.
The grid is better if you want perspective. You look at it occasionally and it resets your sense of scale.
The number is better if you want presence. It changes while you look at it, which a grid cannot do, and a number that changes is much harder to ignore than a picture that does not. A week counter in decimal form, such as 1,782.61, moves in the second decimal place about every hour and a half, which is enough to feel alive without being frantic.
One caution
Any of these tools works by being seen, and anything that is seen constantly stops being seen. If you set up a week counter or a grid and stop noticing it after a fortnight, that is normal. Moving it, changing its style, or hiding it for a month and bringing it back all restore the effect. Choose something you can adjust easily rather than a poster you have to reprint.
If you want the ticking version
TimeBorn counts in years rather than weeks, with two to ten decimal places, as a live wallpaper or a home-screen widget. The same 34-year-old would see roughly 34.164 rather than 1,782.6, and at higher precision the last digits move continuously. Twenty-four faces are drawn from scratch, and the counter can be dragged, resized and rotated to sit wherever the grid or the number belongs on your own photo. It is free, has no ads, and never connects to the internet.