Fish Weight Calculator

Use the form below to calculate how much a fish weighs based on its length and its girth. If you do not know the fish's girth, leave it blank and it will be approximated for you.

Calculated weight: -

Fish Weight Calculations

The fish weights are calculated with the formulas below. If a fish girth is not specified, the default value Fish Girth = 0.58 × Length is used.

Trout, steelhead, mackerel, snook, redfish, bonefish
Fish Weight = Length × Girth × Girth / 900
Salmon, bass
Fish Weight = Length × Girth × Girth / 800
Walleye
Fish Weight = Length × Length × Length / 3500
Pike, gar
Fish Weight = Length × Length × Length / 2700
Sunfish, bluegill
Fish Weight = Length × Girth × Girth / 1200

You can also calculate the weight of tarpon and other saltwater fish.