Tutorials
Watch it done once.
Calibrating takes about a minute and you only do it once. Everything after that is taking a photo.
Start here
How to calibrate your hand
Start here. You photograph your hand next to any wallet-size card, and Caudal measures your hand once so it can use it as a ruler from then on. You only ever do this once.
Quick ones
Under a minute each.
Calibration, in under a minute
The same calibration step, condensed.
Measure a live fish
Take the photo in the app and get length, weight and species.
Measure a fish from an old photo
Any photo where your calibrated hand is holding the fish — even one from years ago.
More on our YouTube channel.
Ready to try it?
Caudal is free on iPhone and Android.
