Fish weight without a scale

I came across an interesting method of determining your catches weight without a scale. And it seems close enough for most bragging rights when a scale isn't in your tackle box. It works with most cylindrical fish such as Bass. But it is not useful for flat fish such as a flounder.

The girth squared method:

Need: A cloth tape measure that you can wrap around the fish.

weight = (length x girth^2)/k

Length is length of fish

Girth is the girth of the largest cross section of the fish

K is the constant 800 for "normal" shaped fish (bass, trout, etc)

K is 900 for fish like (pike, Gar, etc)

Example:

You catch a Bass 15 inches long and a girth of 16 inches. You can estimate its weight by the formula:

Weight = (15 x 16^2)/800 = (15x256)/800 = 3840/800 = 4.8 pounds.

Not bad for our 6wt fly rod.

Use it, take it with a grain of salt.