FishRuler: Fish Size MeasureFishRuler: Fish Size Measure
Forgot the tape measure at the cabin? No worries. Point your iPhone at your catch, tap the nose and the tail, and read the length in centimetres — then keep every catch in your own logbook, right on your phone.
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Features
Tap the nose, then the tail
Aim the camera at your fish, then tap once at the nose and once at the tail. The distance between the two points appears on screen in centimetres. No reeling a tape back in, no struggling to hold it straight.
A little off? Drag it over
If a tap lands slightly off, drag the marker into place — no need to start over. A line joins the two points, so you can see exactly what you measured at a glance.
Measure and release quickly
Press Reset and the measurement clears, ready for the next one. Since you're not pinning the fish flat on a board, it spends less time out of the water.
Keep a logbook of every catch
Save the species, length, a photo, where you caught it, and when — all in a logbook that lives right on your phone. Look back on the whole season, or just one great day at the lake, any time.
See your personal bests
FishRuler checks each new catch against your logbook and flags it when it's your biggest yet for that species. A simple way to watch your personal records add up over time.
Turn a catch into a shareable card
Export any logged catch as a clean image card with the photo, species, and length, then share it however you like using your phone's own share sheet.
Reference release-size info, where available
For a small number of species and regions where an official minimum or slot size is publicly documented, FishRuler can show it alongside your measurement as a reference point — never as a guarantee. Coverage is limited and grows slowly on purpose: we'd rather show nothing than a figure we can't source properly.
Runs fully offline
Use it on a rocky shoreline, up a river, off the dock, or out on the lake — anywhere with no signal. No account, no sign-up, and your logbook never leaves your phone unless you choose to share a card.
Fish and everything else
Measure rods, tackle, the cooler, boat hardware — whatever's in front of you. Useful well away from the water any time you need a quick length.
Pay once, no ads
Buy it once and it's yours. No subscription, no add-on purchases, no ads.
You landed the fish. Now how long is it — and will you remember by next season?
Cold wet hands, a walleye that won't lie still, a tape measure that's somewhere in the bottom of the boat — measuring a fish is never as simple as it sounds, and the fish is out of the water the whole time you're fumbling.
FishRuler turns your iPhone into the measuring tool you already have with you. Point the camera at your catch, tap the nose, tap the tail, and the length appears on screen in centimetres. Save it to your log with one tap and it's never lost again.
HOW IT WORKS
- Tap two points, nose and tail, and read the distance between them
- Missed the spot? Drag either marker to fine-tune it without starting over
- A line is drawn between the two points so you can see exactly what was measured
- Save the catch with a photo, species, spot and date, or hit Reset and move on
YOUR CATCH LOG
- Every saved catch lives in a scrollable log: photo, species, length, spot and date, all on one card
- FishRuler tracks your personal best per species automatically. Beat your record and the app tells you straight away
- Best-ever catches stand out in the log so your top fish are always easy to find
- Turn any catch card into a single image, ready to share
WHY ANGLERS LIKE IT
- Nothing to unroll, nothing to hold flat, nothing to lose over the gunwale
- Fast enough to measure and release quickly
- Works fully offline, which matters on a lake with no bars of service
- No account, no sign-up. Your log stays on your device
- Useful beyond fish, too: measure rods, coolers, boat fittings or anything else in front of you
Walleye and pike on the lake, lake trout in deep water, perch and bass off the dock, or a hole on the hard water in winter — if it lies flat in front of the camera, you can measure it.
A NOTE ON UNITS
Lengths are shown in centimetres. If you record your catches in inches, note that the reading is metric and convert it yourself.
BEFORE YOU BUY - DEVICE REQUIREMENT
FishRuler measures using the LiDAR scanner, so it needs an iPhone that has one: iPhone 12 Pro / Pro Max or a later Pro model. On a device without a LiDAR scanner the app will tell you it cannot measure. It also requires iOS 17 or later, so please check both your model and iOS version before purchasing.
ABOUT ACCURACY AND REGULATIONS
Readings are real-world estimates produced by the device's depth sensor. Good light, a steady hand and a fish lying flat give the best results. Treat the number as a practical field measurement. For provincial size limits, tournament rules or official record submissions, always confirm with the measuring device those rules require.
ABOUT THE SIZE REFERENCE NOTE
For a small number of species, FishRuler can also show a reference note if a catch falls outside a size range. This is for your information only. It is not a full or authoritative list of regulations and does not replace checking current provincial rules before you keep a fish.
One purchase. No subscription, no ads.