Plans · three tiers · quotas published
The number is free. What to do about it is Pro.
Every calculator that answers a searched question is free forever: complete, no account, no metering. The tiers below are about where your work lives: saving it, naming it, comparing it, and putting your brand on it. No trial, because none is needed.
The book and the Problem Room read the same for every tier today: the preface and chapter 1 free, the rest in print, every problem set open. Free account quotas: 10 saved models · 3 sites · 2 scenarios per system, published, not discovered.
No trial, on purpose
Free already does what a trial does, without the countdown. No usage metering, no email for a download, no blurred previews: every Pro capability is shown as a real, complete, openable worked example.
Your data is never hostage
Downgrade and every saved system stays readable, exportable, and diffable, forever. Pro-model systems open read-only with their stored, version-pinned outputs intact. New saves past quota get an inline choice, never a lost result.
Your brand, not ours
Branded reports carry your logo and accent color; Blueprint attribution is one footer line. The document goes in front of your customer, and our branding does not compete with theirs. Branded reports are live; see a sample.
Public cases on The Field are readable without logging in and indexable. Three calculator pages carry no upsell at all: System Volume, Glycol Dosage, Closed Loop Treatment. Correctness fixes ship to every tier at the same time; we do not sell accuracy. Prices are in US dollars; sales tax is added at checkout where it applies.