FishRuler: Fish Size MeasureFishRuler: Fish Size Measure
Forgot your tape measure? No problem. Point your iPhone at your catch, tap the nose and the tail, and get the length in cm — then keep every catch in your own logbook, right on your phone.
Download on the App StoreScreenshots
Features
Tap the nose, tap the tail
Aim the camera at your fish, tap once at the nose and once at the tail. The distance between the two points shows up on screen in centimeters. No rewinding a tape, no fighting to keep it straight.
Off by a bit? Just drag it
If a tap lands slightly off, drag the marker to nudge it into place — no need to start over. A line connects the two points, so you can see exactly what you measured at a glance.
Measure and release fast
Hit Reset and the measurement clears, ready for the next fish. Since you're not wrestling the fish flat against 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 on your phone. Look back on the season, or just one great day, whenever you want.
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 quiet 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 growing slowly, on purpose: we'd rather show nothing than show a number we can't source.
Works completely offline
Use it on the rocks, up a creek, out on a jetty, or offshore on the boat — anywhere with no signal. No account, no sign-up, and your logbook never leaves your phone unless you choose to share a card.
Not just for fish
Measure rods, tackle, coolers, boat hardware — whatever is in front of you. Handy well beyond the water any time you need a quick length.
One-time purchase, 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?
Reaching for a tape measure with wet hands, holding a thrashing fish flat, keeping the tape straight — it never works the way it should, and the fish is losing time out of the water while you fumble.
FishRuler turns your iPhone into the measuring tool you actually have with you. Point the camera at your catch, tap the nose, tap the tail, and the length appears on screen in centimeters. 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 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 in one card
• FishRuler tracks your personal best per species automatically. Beat your record and the app tells you right 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 overboard
• Fast enough to measure and release quickly
• Works fully offline — no signal needed at the lake, river or jetty
• No account, no sign-up. Your log stays on your device
• Useful beyond fish, too: measure gear, coolers, boat fittings or anything else in front of you
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 later Pro models. 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
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 tournament rules, legal size limits or official record submissions, always confirm with the measuring device that the rules require.
ABOUT THE SIZE REFERENCE NOTE
For a small number of species and regions, FishRuler can show a reference note if a catch falls outside the usual take-home size range. This is for your information only — it is not a full or authoritative list of regulations, and it does not replace checking current rules with your local fisheries authority before you keep a fish.
One purchase. No subscription, no ads.