How many weeks old am I?

Weeks old versus weeks on a life calendar

This calculator counts continuous weeks: the number of days since your birth divided by seven. A life calendar grid counts slightly differently. It restarts every row on your birthday and gives each year exactly 52 boxes, so the extra day or two each year is folded into the last box. After 40 years the continuous count is about 2,087 weeks while the grid shows 2,080 filled boxes. Both are right; they answer slightly different questions.

Thousand-week milestones

Week 1,000 arrives at about 19 years and 2 months. Week 2,000 comes at about 38 years and 4 months, week 3,000 at about 57 and a half, and week 4,000 at about 76 years and 8 months, close to the average American life span. Each one is a natural moment for a look back at the last thousand weeks and a plan for the next.

The list above crosses off milestones you have passed and dates the ones to come. To see them all on one page, make a life calendar from your birth date; to look up any age, use the weeks lived by age table.

Why weeks?

A week is the unit most of life is actually organized around: work weeks, weekends, weekly routines. That makes it the most intuitive unit for thinking about a whole life, small enough to feel and large enough to count. It is also why the 4,000 weeks idea has resonated so widely.