Hey all, If a fish weight calculator shows an estimated weight that is a pound over the actual measurements. Would it not make sense that taking a pound off another estimate of actual measurements would give a semi accurate weight?

It seems logical that it would work that way, but I really doubt it. A fish calculator is at best, an estimate. To try and extrapolate a standard deviation for different weights seems pert near impossible.  Iguess it all depends on what you mean by "semi accurate"  

If an actual smallmouth I caught weighs 3lb 7oz and I plug in its numbers into the calculator the calc is over by one pound.  If I then put in the attributes of a lunker I recently caught but could not weigh,  and remove a pound from the equasion, would that not give me a ballpark weight for the lunker?

Hey all, If a fish weight calculator shows an estimated weight that is a pound over the actual measurements. Would it not make sense that taking a pound off another estimate of actual measurements would give a semi accurate weight?

Take off a pound? Are you crazy?

I have a perfect "weight calculator" right her between my shoulders and it's perfectly accurate. The bass is always a pound larger, we all know that.

Seriously, I don't know.  Like Avid said, it's all a big estimate.  I've seen bass that were short and chunky, long and chunky, and bass that have chunks in different spots.  Of course (not that I know anything about smallies having only caught one in my life) I would assume that their bodies are made up a little bit differently.  The only way to be certain is to weigh on a precise set of digital scales.  Of course, mine are always broken.    

The answer is no. The reason is what Fisher of Men described in his post:

I've seen bass that were short and chunky, long and chunky, and bass that have chunks in different spots. Of course (not that I know anything about smallies having only caught one in my life) I would assume that their bodies are made up a little bit differently. The only way to be certain is to weigh on a precise set of digital scales.

Using the same fish calculator you will get some fish estimates that are over the actual weight and some that are under it, due to the different characteristics of each fish's body.

The bigger the fish, the bigger the margin of error. If you could catch enough of 1 species of bass of enough differnt sizes and builds, then use your estimator to calc the weight as well as weigh them, then you could get an average percent difference between actual and estimated weights. At this point you would have a pretty good estimator correction figure. Then you could also figure up a length to girth relationship or ratio to characterize the average deviation from your average percent correction figure for Bass of different proportions...or you could just get a scale.

Well, the lunker in question was 22" long with a girth around 16".  Smallmouth bass records from state to state are all in the 21"-23" area and weigh from 5lb 10oz- 7lb 3oz.  I figure it is at least fair to say it could have been 6 lb fish.  I catch the 19" ones pretty often in this one hole and they all weigh over 3lbs.  The last one I weighed was 18.5"L x 14" G x 3lb 7 oz.  

Buy a scale - then you won't be trying to kid yourself.

I actually did buy a scale after that fish.  I got a digital I keep it with me at all times now.  Thats how I knew the weight of the 3lb 7oz fish. I was just trying to estimate the weight of the 22" fish.

To try and extrapolate a standard deviation for different weights seems pert near impossible.

avid's word of the day: extrapolate  

Ok, I am going to tell you all the real reason why weight calculators dont work. ;D  This gizzard shad came out of an 11.9 lb fish. The weight calcualtor don't know if this one pound shad or one even bigger was just eaten by the fish or not. Largemouth bass have been reported to eat a gizzard shad up to half their length in size and I am sure some California fish eat some big trout up to a couple pounds as well. I have caught big smallmouths on big sucker minnows about half their size as well so I think this proves guessing and weight calculators don't work.