Education
Crystalcal: calibration trainer
Ten quick drills. Calibrate your gut.
| Platform | iPhone (iOS 17+) |
|---|---|
| Price | Free, no subscription |
| Account required | No |
| Works offline | Yes |
| Subscription | None |
| Last updated | 2026-03-02 |
ios· Free · all features included ·By All Things AI, Inc ·Released 2026-03-02
Accessibility: iPad layout · Browser version How we checked →
Use Crystalcal in your browser — no install. Sign in and it works right here. Everything stays in your browser; nothing is sent to our servers.Free. All features included.
No subscription, no in-app purchases, no paid tiers. Everything you see works the moment you install it.
About this app
What Crystalcal does
Crystalcal is the daily calibration training routine. Ten known-answer drills per session — coin flips, geography facts, dice rolls. You assign probabilities; the app scores you with the log score. Across many sessions, you watch your calibration tighten.
Features
Built to be useful, not noisy.
Today
Tab Today
About
Tab About
Why it exists
The problem
Forecasting is a learnable skill but consumer practice tools are nonexistent. Crystalcal is the daily drill.
What's different
How Crystalcal stands out
Pure drill format. Not Metaculus. Not Good Judgment Open.
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FAQ
Questions about Crystalcal
How much does Crystalcal cost?▾
Crystalcal is free. All features are included from day one — no subscription, no in-app purchases, no paid tiers. Everything you see in this listing works the moment you install it.
Where does Crystalcal store my data?▾
On your device. Crystalcal is built privacy-first: no account is required, no analytics SDKs, no third-party trackers. Nothing is uploaded to a server we control — the app works without one.
What platforms does Crystalcal support?▾
iOS, on iPhone and iPad. You can find the latest availability on this page.
How do I get support for Crystalcal?▾
Use the Support link on this page, or email support@allthingsn.com. We answer every message and keep responses on the same thread.
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