FishRuler: Fish Size MeasureSupport
Got a question about FishRuler (fish size measuring), or found a bug? Have a look through the FAQs below, then shoot us an email — happy to help. If it won't measure at all, first thing to check is whether your iPhone has a LiDAR scanner.
FAQ
Which iPhones does it work on?
FishRuler measures with the LiDAR scanner, so you need an iPhone that's got one. That's the Pro models: iPhone 12 Pro / Pro Max and newer. On a phone without LiDAR you'll get "This device does not support LiDAR" and measuring won't work. Worth checking your model before you buy.
How do I use it?
Point the camera at the fish and tap once on the nose, once on the tail. A line is drawn between the two points and the distance comes up in centimetres. If a tap's off, drag the marker to fine-tune it, and hit Reset to clear it for the next fish.
How accurate is the number?
The figure on screen is a guide, based on what your phone's depth sensor actually reads. You'll get steadier results in good light, with a steady hand, and with the fish laid as flat as you can get it. Treat it as a practical number for out on the water.
Can I use it for comp measuring or legal size limits?
Please don't. For tournament measuring rules, legal size limits, or official record claims, always confirm with the measuring device those rules call for. Checking the regs where you fish is on you as the angler.
Does it work where there's no reception?
Yep. FishRuler runs completely offline. Off the rocks, up a freshwater creek, on the breakwall or out wide on the boat — it measures the same with no bars at all.
What does it cost? Is it a subscription?
It's a one-off purchase. Buy it once and there's nothing more to pay. No subscription, no in-app purchases, no ads.
Do my photos or measurements get sent anywhere?
No. FishRuler collects no data at all and sends nothing off your phone. The camera feed is processed on the device purely for measuring, and the app never saves it.