FishRuler: Fish Size MeasureFishRuler: Fish Size Measure
Left your tape measure at home? Not a problem. 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, tap the tail
Point 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 winding a tape back in, no wrestling to keep it straight.
Slightly out? Simply drag it
If a tap lands a little off the mark, drag the marker to nudge it into place — there's no need to start again. A line joins the two points, so you can see at a glance exactly what you've measured.
Measure, then release
Tap Reset and the measurement clears, ready for the next fish. As you're not pressing 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 over the season, or just one good day, whenever you fancy.
See your personal bests
FishRuler checks each new catch against your logbook and flags it up when it's your biggest yet for that species. A quiet way of watching your personal records build up over time.
Turn a catch into a shareable card
Export any logged catch as a tidy 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 areas 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 show a figure we can't source properly.
Works entirely offline
Use it on rocky marks, up a river, off the pier or out on the boat — anywhere without a 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, cool boxes, boat fittings — whatever happens to be in front of you. Useful well away from the bank whenever you need a quick length.
One-off purchase, no adverts
Buy it once and it's yours for good. No subscription, no additional purchases, no adverts.
You've landed it. Now how long is it — and will you remember by next season?
Wet hands, a fish that won't stay still on the mat, a tape that curls up the moment you let go — measuring a fish is never as simple as it sounds, and the clock is running while you fumble with it.
FishRuler turns your iPhone into the measuring tool you always have on 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 is never lost again.
HOW IT WORKS
- Tap two points, nose and tail, and read the distance between them
- Tapped slightly off? Drag either marker to fine-tune it without starting again
- A line is drawn between the two points so you can see exactly what was measured
- Save the catch with a photo, species, swim and date, or hit Reset and move on
YOUR CATCH LOG
- Every saved catch lives in a scrollable log: photo, species, length, swim 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 GET ON WITH IT
- Nothing to unroll, nothing to hold flat, nothing to lose in the margin
- Quick enough to measure and get the fish back in the water
- Works completely offline, so it is fine on a remote stretch of river with no signal
- No account, no sign-up. Your log stays on your device
- Just as handy off the bank: measure rods, bivvies, cool boxes or anything else in front of you
Coarse anglers, carp and pike sessions, match days on the bank, or a bit of sea fishing off the pier — if it lies flat in front of the camera, you can measure it.
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
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 bankside measurement. For match rules, size limits or official record claims, always confirm with the measuring device those rules require.
ABOUT THE SIZE REFERENCE NOTE
For a small number of species, FishRuler can show a reference note if a catch falls outside the usual size limit under current national byelaws. This is for your information only. It is not a full or authoritative list of regulations and does not replace checking the current rules before you keep a fish.
One purchase. No subscription, no adverts.