# Sizewise Life in Weeks

> Your life as a grid of weeks: one row per year, with milestones and exact counts. Draws a life-in-weeks grid from a birth date — one row per year, 52 boxes per row — with the current week, your milestones and exact counts of days, weeks, Sundays and leap days lived. Nothing is stored.

Part of usefulweb.app (https://usefulweb.app/). Part of [Sizewise](https://sizewise.usefulweb.app/) (ownerApp: sizewise). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://sizewiselifeweeks.usefulweb.app/ (interactive tool at https://sizewiselifeweeks.usefulweb.app/tool)
- JSON API: POST https://sizewiselifeweeks.usefulweb.app/api/v1/calculate with a JSON object of inputs (schema: https://sizewiselifeweeks.usefulweb.app/api/v1/tool)
- OpenAPI: https://sizewiselifeweeks.usefulweb.app/openapi.json
- MCP (Streamable HTTP): https://sizewiselifeweeks.usefulweb.app/mcp - tool `sizewise_life_weeks`

## Inputs
- birthDate (date): Birth date
- today (date): Count up to (empty = today)
- years (integer): Years in the grid
- milestones (textarea): Milestones (one per line: date, then a label) - For example “2012-09-01 First job”.

## Method
- Rows start on each birthday (29 February birthdays fall on 28 February in common years); box n of a row covers days 7(n−1) to 7n−1 after the birthday, and the 52nd box also holds the last one or two days of the year.
- Days, Sundays and leap days are exact counts of UTC calendar days from the birth date to the chosen day, both included for Sundays and leap days. Full Moons are days lived ÷ 29.530589 (mean synodic month, Meeus).
- The grid length is your choice (90 years by default); it is not a life-expectancy estimate.

## Limits
- Nothing you enter is stored on the server beyond the request itself. The grid is a way to picture time, not a prediction.