Measure your catch from a photo.
No tape measure. No bump board. No scale. Caudal estimates a fish’s length and weight from a single photo, so you can measure, log and release in seconds.
Caudal is developed by Phalanx Fishing LLC.
Inside the app
What measuring actually looks like.
Swipe through the app, screen by screen.
How it works
Three steps from catch to record.
Point, shoot, done — or measure straight from a photo you already have.
- 1
Calibrate once
Photograph your hand next to something of a known size. Caudal remembers it, and you never do this step again.
- 2
Photograph the fish
Hold the fish and take the shot, or pick a photo from your camera roll — old ones work too.
- 3
Get length and weight
Caudal finds the fish, measures it against your hand, and saves the result to your catch log.
Built for accuracy
Your own hand is the ruler.
Most measuring apps make you line up two points by hand. Caudal uses a reference it can actually trust — the hand already holding the fish. Caudal’s core measurement methods are patent-pending.
Works on any iPhone or Android
One calibration photo is all it takes. On iPhone Pro models, Caudal also uses the LiDAR sensor for even greater accuracy.
Straight or body-contour length
Report a straight nose-to-tail measurement, or follow the curve of the body when the fish isn't lying flat.
Species ID on your device
Caudal identifies the species without sending your photo anywhere — so it works with no cell signal at all.
Weight, not just length
Caudal estimates weight from length and the fish's measured body depth, and learns from any weights you enter yourself.
Your logbook
Every catch, logged.
Species, measurements, date, location and tide, saved with the original photo. Your log syncs privately to your account, so a new phone doesn’t mean starting over — and you can export it whenever you like.
Available now
Get Caudal, free.
Measure, log and release in seconds — on iPhone and Android.