Frequently asked questions

Annoying, and fixable. Almost always the purchase sits on a different Apple Account than the one signed in on the device.

1. Open the paywall in the app and tap “Restore purchases”.
2. Check under Settings → your name that you are signed in with the Apple Account you bought with. A subscription cannot be moved between accounts — not by you and not by us.
3. Close the app completely and open it again.

Still stuck afterwards? Then it is a bug on our side and we want to see it. Write to support@cal3d.app.

In the App Store, not with us — we have no access to it. Deleting the app does not cancel anything; the subscription lives in your Apple account and keeps renewing.

1. Open Settings and tap your name at the top.
2. Tap Subscriptions.
3. Choose Cal 3D, then Cancel Subscription.

Or open the list directly: apps.apple.com/account/subscriptions.

Apple decides refunds, not us — Apple is your contractual partner for the purchase. The fastest route is reportaproblem.apple.com: sign in, pick the purchase, state the reason.

Independently of that you have a statutory right of withdrawal — and because the purchase contract is concluded with Apple, it is exercised there. What it covers, where to send it and when it expires early is on the cancellation and refunds page.

No — the App Store and Google Play are separate billing systems, and a subscription bought in one cannot be carried into the other. You would cancel on the old side and subscribe on the new one.

Prices are set once the app is in the store — you will see them there before buying. We are not putting a number here while it is not binding.

It measures the portion instead of assuming it. A flat photo has no scale — the same bowl of rice can weigh 120 or 280 grams and look identical in the image.

One sweep around the plate gives the app the volume from the camera’s depth data. Volume times density gives a weight, and that weight is split across the ingredients the model recognises.

The whole calculation is laid out on the method page.

Then you correct it before saving — every ingredient and every amount is editable.

Worth knowing where the limit sits: measuring fixes the scale, not the recognition.

If the model takes couscous for cauliflower rice, the portion is measured exactly and the calorie figure is still off. That is why the entry stays editable instead of being presented as final.

Honest answer: we do not have a solid figure of our own yet, and we are not inventing one.

What we have measured is the problem: the photo pipeline from which Cal 3D inherited its ingredient recognition sat at roughly 30 % calorie error across 28 weighed plates from the public Nutrition5k dataset — with a clear pattern, not random noise. That pattern is exactly what the measurement attacks.

As soon as a series of our own exists, it will appear with the date, the number of plates and a description of the setup on the method page.

Because a measurement says so. If the sweep worked, the entry carries the line Measured by the scan with the volume it found; if the numbers were computed offline, it says Calculated from the offline food database.

If neither line is there, nothing was measured. Every check in the code fails towards no line rather than towards a claim — a number presented as measured has to have actually been measured.

No. You can log any meal by hand or scan a barcode.

The sweep is the route to a measured portion — it is an option, not an obligation.

Anything inside an opaque container is invisible to the camera. With soups and drinks the app measures the visible content; with cups, entering the amount by hand is more accurate.

With layered dishes — sauce over rice, cheese over a bake — it measures the outer shell. What lies underneath stays an estimate by the model.

The app needs iOS 17 or later. Volume measurement additionally requires a LiDAR sensor, which is fitted to the Pro and Pro Max models from the iPhone 12 Pro onwards — so not to older Pro models such as the iPhone 11 Pro.

On every other device Cal 3D works fully — no entry there ever carries the Measured by the scan line, because nothing was measured. We say this before you buy, not after.

That is your call, and we do not want to make it for you: without LiDAR you still get barcode lookup, the food database, the diary and the photo recognition — everything except the measurement that makes Cal 3D special. That one needs the Pro and Pro Max models from the iPhone 12 Pro onwards. Cal 3D is a subscription app either way; what you lose without LiDAR is the measured portion, not the app.

Yes — Cal 3D is on Google Play. What you get there is the photo version: one picture of the plate, and each food comes back with its own grams and calories.

The 3D measurement — walking the phone around the plate — is iPhone-only today. That is a hardware question rather than a scheduling one: depth sensors vary far more across Android devices than across iPhones, and a measurement we cannot vouch for is worth less than an honest estimate.

The volume maths is written in Swift, on the iPhone side. The shared C++ core meant to carry it across is still a placeholder — we would rather say that than let you read a plan as a status.

For recognising the dish, yes — a vision model runs on a server for that. For the measurement, no: that happens entirely on your device.

Without a connection you can still log by hand and keep your diary.

If you were signed in, sign in again with the same account — your diary comes back from the sync.

If you were not, they are gone and we cannot get them back: without an account we keep no copy of your diary. We would rather name that than hide it.

A device backup preserves it either way: an encrypted iCloud or computer backup includes the app’s data. If you restore the iPhone from such a backup, the diary comes back with it.

Planning to reinstall? Make a backup first. Deleting the app also does not cancel a subscription — see above.

Three things, in this order — the first two are quick:

1. Close the app completely (swipe it away in the app switcher) and reopen it.
2. Check for an iOS update and for an update to Cal 3D in the App Store. Most crashes we have seen were fixed in a version already released.
3. Restart the iPhone. Only then consider reinstalling — and read the previous answer first, because reinstalling deletes your diary.

If none of that helps, write to support@cal3d.app with your iPhone model and iOS version. That usually saves two emails.

Three things can leave your device, each only when you ask for it: a single compressed photo of your meal, a food name you type into the search, or a workout you describe in your own words. Each goes through our own endpoint to OpenRouter and from there to Google Gemini so it can be recognised. We do not store any of them and write nothing to a log.

What we are not claiming: that the providers do not use them for training. We cannot assure that, so we do not write it down — and for typed text the intermediary makes no retention promise at all, while for images it does. Details, including who receives what, are in the privacy policy.

What never goes to a model: the measurement itself, your diary and your body weight — the calories for a workout are worked out on your iPhone. If you sign in, your diary is synced to your own devices instead, which is a different path entirely and set out in the privacy policy; photos are never part of it.

No — an account is optional. Two things need one: the sync between your devices, and rewards for referring a friend. Everything else works without.

An account is optional. It syncs your diary, profile, water, workouts and weight history between your devices and brings them back after a reinstall; rewards for referring a friend need one too. You create it with Sign in with Apple, Sign in with Google or a one-time code by email, and you can delete it in the app at any time under Profile → Account Actions → Delete Account.

Only if you sign in. Without an account your diary stays on the phone, with the downside we have always named: delete the app or lose the phone and it is gone.

With an account your diary, foods, water, workouts, weight history and profile are kept for you at our processor in Frankfurt and synced to your other devices. Photos are never synced — neither the images nor their file paths — and what does leave the phone either way is listed in the privacy policy.

In the app via Profile → Account Actions → Delete Account, or by deleting the app. Both are described step by step on the delete your data page.

Only for counting: there is a cap of 120 analyses per day so that nobody can drain the service. The address itself is not stored but passed through a one-way function — it cannot be recovered from the result.

It is not published yet. We will name a date when we can keep it — which is also why this site shows no ratings and no user numbers.

Gladly. The most useful thing is weighing a plate, scanning it and sending us both numbers — that is how the measurement series still missing from the method page gets built. Write to support@cal3d.app.