The Independence Number
is the one nobody gave you.
How much strength and balance do you need today to still be doing things for yourself at 85?
Fifteen minutes. A chair and a tape measure. No signup. You see your results first.
I'm 47, two young kids, and I have a spreadsheet for retirement. I know what I need saved by 60.
Recently I started thinking about whether I'd be strong enough to enjoy retirement. How long will I be able to do things for myself? Driving. Stairs. Getting off the floor without a hand. I couldn't find a number, so I read the research and built this.
It won't predict your lifespan and it won't give you one score. No published method exists for combining these tests. Every row shows how strong its own evidence is.
What a result looks like
SAMPLE · man, 47, at the published median for his age · target age 85
| Row | Your value | Range for 47 | Need today for 85 | Evidence | State |
|---|---|---|---|---|---|
| Gait speed | 1.43 m/s | 1.30–1.57 · 50th pct | 1.63 | strong · 23,111 people | ● Behind by −0.20 |
| Aerobic capacity | 33.7 mL/kg/min | 28–41 · 50th pct | 34.4 | strong · 16,278 tests | ● Behind by −0.70 |
| Sitting-rising | 8 of 10 | ≥ 8 | 8 | limited · one clinic | ✓ On track by +0.0 |
Six more rows on the full panel.
Every number above is a published median for a 47-year-old man. Not a real person. And not a flattering picture. Average is already behind.
This form needs JavaScript, and a database this server can reach. If you are seeing this sentence, one of the two is missing.
Come back to it
Most people read this at a desk. The test needs fifteen minutes, a chair and a bit of floor. So if this is not the moment, leave your email. You will get new writing a few times a year, and every piece links back here. Nothing else, and one click unsubscribes.
Double opt-in: you will get one email asking you to confirm, and until you click it you are on no list at all. Every email carries a one-click delete link, including that first one.
The argument, at length
Why the number exists, and where the research behind it gets quoted wrongly.