for iPhone & Apple Watch
Barcode scanning and food search are free here. Most trackers moved them behind a subscription. Calvin does not.
Coming soon to the App Store, for iPhone and Apple Watch.
Point at a packaged food and log it. No paywall, no scan limit.
USDA Branded, with Open Food Facts as a fallback.
Protein, carbs, fat, fiber, sugar and sodium on every entry.
Recents, usuals and common foods are one tap. Copy yesterday's whole log when today is empty.
A smoothed trend line instead of the daily noise the scale gives you.
Maintenance calories are back-calculated from your real weight trend, so imperfect logging self-corrects against the scale.
Reads activity and energy, and imports weigh-ins automatically.
Home and Lock Screen widgets, Shortcuts support, and your data out whenever you want it.
Search, scan a barcode, or pick from what you usually eat at this time of day. Calvin learns your patterns, so the food you want is normally already on screen.
Macros fill in automatically. Adjust servings and you're done.
Daily weight is noisy — water, salt, sleep. Calvin fits a trend line through it and reads your real rate of change.
Then it works backwards to your actual maintenance calories. Log imperfectly and the number still converges, because the scale is the thing being trusted, not your logging.
Steps, active energy and workouts come from Apple Health, so what you burn is folded into the day without double-counting a workout you already logged.
Fitbit, Whoop and Hevy connect directly if you use them.
The ring reads today against your goal where you have set one, and against your own recent typical day everywhere else. Tap a metric to point the whole screen at it.
Underneath, a week per metric — labelled bars, your goal, your daily pace. Today's bar is drawn as an outline, because a day that is still going is not a short day.
There is no sign-up and no login. Your food log lives on your phone, not on a server — and Calvin does not sell, share, or advertise against it.
Some features do call a server: AI photo scanning, food and barcode lookups, and the optional Fitbit, Whoop, Hevy and Google Health connections. The privacy policy sets out exactly what each one sends and what is kept.
An optional subscription, with a 3-day free trial. Everything above stays free whether or not you subscribe.
Yes. Barcode scanning is free in Calvin with no scan limit and no subscription, and so is food-database search. Both sit behind a paywall in several of the largest trackers. Scans resolve against the USDA Branded Food Products Database, with Open Food Facts as the fallback when a product is missing.
No. Calvin has no sign-up and no login, and your food log is stored on the iPhone rather than on a server. Nothing is uploaded, sold, shared, or advertised against. The trade-off is that there is no cloud backup: keep iCloud device backup on, or export a CSV from Settings.
Calvin Plus is $9.99 a month or $59.99 a year, with a 3-day free trial. It adds AI meal-photo scanning that reads a whole plate into separate foods, deeper trend insights, and direct connections to Fitbit, Whoop and Hevy. Everything listed as free stays free whether or not you subscribe.
After roughly three weeks of weigh-ins, Calvin fits a trend line through your daily weight, reads your real rate of change, and works backwards to your actual maintenance calories instead of trusting a formula. The scale is what gets trusted, so imperfect logging still converges on a usable target.
Yes. Calvin reads activity, active energy and weight from Apple Health, imports weigh-ins automatically, and folds a workout into the day once rather than twice. There is an Apple Watch app, Home and Lock Screen widgets, and Siri and Shortcuts support. Apple Health data is read on device and never sent to Calvin's server.
Not yet. Calvin is an iPhone and Apple Watch app, and it is coming soon to the App Store. There is no Android, web or desktop version at launch. CSV export exists from day one, so a log started in Calvin can be moved elsewhere without being locked in.
Free to start, no account to make.
Coming soon to the App Store.
Calvin