How to pick the life-expectancy number
The most arbitrary input in the lifetime view is “how long you plan to live”. That number sets the total cell count of the grid and becomes the denominator of the progress percentage, so the picture’s whole impression shifts with it.
Start from the statistics
By most national life tables, a child born today has a life expectancy somewhere in the low-to-high 80s. But that is the figure for a newborn. Someone who has already reached a given age has already survived the mortality risk up to that age, so adding their remaining life expectancy pushes the total above the headline number. A 40-year-old’s remaining life expectancy is around another 40-odd years, which lands the total in the high 80s.
The tool defaults to 100. That is a generous ceiling, well above the statistical figure, so almost everyone is left with visible empty cells, and the grid divides cleanly into rows. If you want something closer to the statistics, drop it to 85–90 on screen.
Should you adjust for yourself
You can nudge the number for family history, lifestyle, or current health. But precise longevity prediction is not the point of this tool. The point is a sense of scale for the time you have left, and for that, 90, 100, or 110 lead to the same conclusion: there are fewer cells left than you assumed.
Compare two values
What is actually useful is switching between values. Set expectedAge to 80 once and 100 once, and you see exactly how much of the grid a decade is worth — usually about a row and a half. Whether that row and a half feels large or small to you says something about your current stance toward time.
Don’t trust the percentage too much
A percentage is convenient but misleading. “36% of a life is behind me” quietly assumes the remaining 64% will have the same quality as the first 36%. It will not. Stamina, recovery, the density of relationships, the cost of learning something new — all change over time. The cells near the end of the grid are the same size as the ones at the start, but they do not hold the same content.
That is why the tool does not lean hard on the progress bar. Better to sit with the shape of the filled and empty cells than with a single number.
The guide covers the rest of the lifetime input.