Support

FishRuler measures using the LiDAR scanner, so it needs an iPhone that has one. That means the Pro models: iPhone 12 Pro / Pro Max and later. On a device without LiDAR you'll see "This device does not support LiDAR" and measuring won't be available. Please check your model before purchasing.

Yes — FishRuler requires iOS 17 or later, since the logbook is built on Apple's newer on-device storage framework. If your iPhone can't update to iOS 17, the app won't install. Most LiDAR-capable iPhones run iOS 17 without any trouble, but it's worth checking your software version before purchasing.

Point the camera at the fish and tap once at the nose, once at the tail. A line is drawn between the two points and the distance is shown in centimetres. If a tap is off, drag the marker to fine-tune it, and press Reset to clear the measurement for the next fish.

Yes. When you save a measurement, it's added to your logbook along with a photo, species, location name, and date, so you can browse past catches any time. Nothing is saved automatically — you choose which measurements to log.

Whenever you log a catch, FishRuler compares its length against the other entries you've logged for that species and flags it if it's your longest yet. It's based only on what you've logged in your own logbook, not on any outside database.

It's drawn from a small set of publicly published regulations — national freshwater fishing rules and shared regional conservation sizes, for instance — for species and areas we could clearly document. It's shown purely as a reference alongside your measurement, not as an official ruling, and it isn't available for every species or region. Always check the current regulations that apply where you're fishing.

The value on screen is a guide, based on what your device's depth sensor actually measures. Results are steadier in good light, with a steady hand, and with the fish laid as flat as you can manage. Treat it as a practical number for use out on the water.

Please don't use it for that. For tournament measuring rules, legal size limits, or official record claims, always confirm with the measuring device those rules require. Checking the regulations in effect where you fish is up to you as the angler.

Yes. FishRuler runs completely offline. Rocky shorelines, backcountry streams, docks, out on the boat — it measures the same with no service at all.

It's a one-time purchase. Buy it once and there's nothing further to pay. No subscription, no in-app purchases and no ads.

No. Your logbook — photos, species, lengths, locations, and notes — is stored only on your device. Nothing is sent to us or to any outside server, there's no account to sign in to, and the only time an image leaves your phone is if you choose to share a catch card.