About This Site

This site exists because most life-in-weeks tools do one of two things wrong. Either they hard-code a lifespan and present the result as if it were about you, or they hand you a grid with no way to know whether the arithmetic underneath it is sound. This one makes the horizon an explicit setting you choose, and shows its working for every number it prints.

It is built and maintained by an independent developer who makes small, focused web tools. It is not affiliated with any of the life-calendar posters or books that popularised the format.

How the numbers are produced

• Days alive: whole calendar days between your birth date and today. Every date is anchored to UTC noon before subtraction, so a time-zone offset or a daylight-saving change can never shift a count by one day.
• Weeks lived: days alive divided by seven, rounded down — completed 7-day blocks only. At 13 days old you have lived one week, not two.
• The grid: 52 columns by one row per year of the expectancy you set. A 52-column row is about 1.25 days short of a real year, an approximation every printed life calendar shares; the stats panel is unaffected because it uses real dates rather than grid squares.
• Milestone days: your birth date plus exactly 10,000 or 20,000 calendar days, leap days included — not a multiplication by 365.
• Saturdays remaining: the calendar Saturdays between today and your birthday plus the expectancy you chose. Since each week holds exactly one Saturday, it is your remaining weeks expressed in a more concrete unit.

All of that logic lives in one small, separately tested module, so the figures on the guide pages and the figures in the tool cannot drift apart — the tables are generated from the same functions at build time.

Accuracy principles

• No lifespan prediction, ever. The expectancy slider is an assumption you choose. We do not adjust for country, sex, habits or health, because a single-number "you have X years left" output would be false precision dressed up as insight.
• Approximations are labelled as approximations. Where a figure rests on the 365.2425-day average year rather than your actual calendar, the page says so and names the constant.
• No invented statistics. If a number cannot be derived from stated arithmetic or pointed at a source, it does not appear on the site.
• Claims get checked. The "138 or 139 days after your 27th birthday" rule on the 10,000-days page was verified against all 35,064 birth dates from 1920 to 2015 rather than assumed from a sample.
• Reflective, not morbid. The grid is an inventory of time, not a countdown. Copy across the site is written with that distinction in mind.

Your data

The calculator is JavaScript running on your device. There is no account, no server call and no database — your birthday, the grid, and both PNG exports are generated locally and never reach us. Details are in the privacy policy.

Corrections

If you find an error in the arithmetic, a date that does not match your own calculation, or a claim that overreaches what the evidence supports, please say so — corrections are welcome and get made. Use the contact page.