Fish Weight Calculator

IGFA Formula

(Tuna, Striped Bass, Marlin)
LUM Formula

(Salmon, Steelhead, Trout)

Striped Bass
Age/Weight Chart PDF

Take measurements as follows:
Girth at the thickest point,
Fork Length from the point of the lower jaw to crotch of the tail.

Girth & Length are Inches


Fork Length



Example: If the fish’s girth is 15 inches and its length is 29 inches, the formula would be used as follows: 15 x 15 x 29,
divided by 800 = 8.16 pounds

IGFA Fish Weight Formula:
((Girth x Girth) x Length) / 800 = weight in pounds

Then the ".16" or "16/100" is converted to ounces (multiply by 16) .16 x 16 = 2.56 or 3 ounces
so this fish is 8 pounds 3 ounces