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. You can also calculate the weight of tarpon and other saltwater fish.
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 / 900Salmon, bass
Fish Weight = Length × Girth × Girth / 800Walleye
Fish Weight = Length × Length × Length / 3500Pike, gar
Fish Weight = Length × Length × Length / 2700Sunfish, bluegill
Fish Weight = Length × Girth × Girth / 1200You can also calculate the weight of tarpon and other saltwater fish.
Record Your Catch in the Fish Swami App
After you've calculated your fish weight, save your fishing trip in the Fish Swami Fishing App! For your next trip, the app can save where you fished, where you caught fish, photos, automatic weather collection, and more.