Pricing
$4 a month. The first 100 keep it forever.
The calculator is free and always will be. So is the 14-day tracking sheet. The app that does the arithmetic for you is $4 a month or $39 a year, with a 30-day refund and no questions.
Monthly
$4
Per month. Cancel any time from your account. No retention flow, no “are you sure.”
Annual
$39
Per year. Two months free against monthly. One decision instead of twelve.
Founding 100
The first 100 subscribers keep $4 a month for as long as they stay subscribed, whatever the price does later. It’s labelled on your account so there’s no argument about it. If you’re reading this before launch, that’s the deal on offer.
What’s free and what isn’t
| Feature | Free | Paid |
|---|---|---|
| Anonymous delta calculator | ✓ | ✓ |
| 14-day tracking sheet (PDF and spreadsheet) | ✓ | ✓ |
| Science page and every citation | ✓ | ✓ |
| Blog | ✓ | ✓ |
| Account and saved history | — | ✓ |
| Two-number daily logging | — | ✓ |
| 14-day baseline and your delta reveal | — | ✓ |
| Trend line (7-day moving average over raw points) | — | ✓ |
| Mass visualiser | — | ✓ |
| Tomorrow’s target max, every day | — | ✓ |
| Protocol card and baseline log downloads | — | ✓ |
The refund is the trial
There’s no free trial. Trials mean card capture, trial-end emails, and cards that expire. Instead you get 30 days, full refund, a self-serve button in your account settings, no email required. Your delta reveal lands on day 14, so you reach the payoff while you’re still fully covered.
What you’re actually paying for
A measurement tool. Not a program, not a plan, not coaching. It stores two numbers a day, computes your delta, smooths the noise, sets tomorrow’s ceiling, and shows the mass you’ve moved as a pile of grapefruit on a table. That’s the product. Everything it doesn’t do is on purpose: no food logging, no streaks, no leaderboards, no badges.
Can you do all of this on the free spreadsheet? Yes, actually. Two weeks of doing it by hand is how you’ll find out whether you want the app.
Not for everyone
Before you subscribe, the signup asks five questions about whether this is the right tool for you. Under 18 is a hard no. A few other answers ask you to talk to a doctor first. Here’s the full list, so nothing surprises you at checkout.
App launch date and signup link will appear here. Prices in USD. Payments handled by Stripe.