Bass Weight Formulas
There is a lot of confusion about weight estimation formulas for bass. The main problem is there are a number of equations out there and no one states what fish species these equations are intended for.
A few years ago I was asked by Doug Stange, Editor in Cheif of In-Fisherman Magazine, to develop a weight estimation formula for giant bass. This was, in part, due to the then-recent record hoax from Spring Lake in northern California. As I was conducting my rsearch on the subject, I ran across a number of weight estimation formulas -- some for bass, some for marlin, some for tuna and others for just about every imaginable fish species known. The interesting thing was the most widely used (and I mean used by the masses, not scientists) formula for bass was actually a formula developed for marlin.
At this point, I knew there was a need to educate anglers that were interested in weight estimation formulas -- teach them which ones were for bass and what the size range they could use with them for accurate results.
That's what this page is dedicated to -- a number of weight estimation equations for each specie of bass in North America and, if known, the accuracy and size range of fish that can be used with the equation.
Largemouth Bass (both Northern Strain and Florida Strain)
There are a number of equations that have been published for use with largemouth bass. Below are the ones that are recognized as accurate and have actually been developed for largemouth bass.
Length Only
Weight =
Credit Doug Hannon, In-Fisherman Magazine vol 14 February 1989.
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Length and Girth
Weight =
Credit Don Peters, IGFA World record Sport Fish 2002.
This formula is the most accurate "overall" for largemouth bass under 14 pounds in weight.
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Weight =
Credit Terry Battisti, In-Fisherman Magazine, December 2004 and March 2005.
This formula is the most accurate for largemouth bass over 16 pounds in weight.
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Smallmouth Bass
Lesser known are the equations for smallmouth bass. Below is the most well-known formula for smallmouth bass. It was developed over a broad sample size and therefore may not represent spring-time fish versus summer fish.
Length Only
Weight =
Credit Anderson, 1980.----------------------------------------------------------------
Spotted Bass
The same can be said for spotted bass as was stated above for smallmouth bass. Below is the "length only" formula to predict the weight of a spotted bass.
Length Only
Weight =
Credit D. Gabelhouse Jr..----------------------------------------------------------------