# Redfish weight estimator



## markbxr400

Have been doing a little web research followed up by my own measurements to translate length of a red to weight.

1. Basic formula - A basic formula I found in several places that works for reds and specs is

Weight in lbs = (length x girth x girth)/800, where length and girth measurements are in inches. Girth is measured at the largest point around the fish.

2. Simplified formula - For a slot red (16-26" in Alabama), the girth of a typical red runs about 0.58 of the length. So a reasonable estimate of weight then is

Weight = (length x length x length)/2378

I have taken about a dozen samples where I measured length, girth and weight and found the basic formula (using actual girth) pretty accurate within about 1 or 2 tenths of a pound. 

I did run into a couple of cases where the simplified formula based on length alone was more inaccurate because the girth of the fish was fatter than the 0.58 of length. This was typically for the bigger (longer) fish toward the top of the slot length, where the girth factor was as large as 0.66 (these were pretty fat fish!).

Anyway, this will quickly get you in the ballpark if you're interested in estimating the weight of your released fish.

The basic formula also works for specs, however, I haven't yet established a typical girth factor yet so that a simplified formula can be established. Will do and update this post as I catch more trout.

Regards,

Mark


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## PaulB

Thank you sir. I suck at math,  but this will come in handy.


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## markbxr400

PaulB said:


> Thank you sir. I suck at math,  but this will come in handy.


Quick example - I caught a 22" red last night. Using the simplified formula,

(22 x 22 x 22)/2378 = 4.5 lbs. The actual weight of the fish was 4.4 lbs.


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## barefoot

Great work...but others have tread this path before you.
Check this link out...pretty cool. I don't agree w/ it's accuracy on trout...but pretty neat site.

http://www.csgnetwork.com/fishsaltwtcalc.html


Then there's the S.Carolina method...

*Estimating Fish Weight*

You can get a fairly accurate estimate of the weight of a fish (in pounds) without having to remove it from the water. Take the following measurements in inches. Measure the length of the fish from the lower jaw to the fork of the tail (Shown as L). Measure the girth by going all the way around the fattest part of the fish (Shown as G). If you can only measure the fish from one side, take the full measurement from top to bottom and double it.








Use the following formula to determine the weight of the fish. 
*(Girth X Girth) X Length) / 800 = weight in pounds *
For example, let’s say you just caught a red drum that measured 36 inches fork length. The girth measured 19 inches. 
*19 X 19 = 361 X 36 = 12996 / 800 = 16.245 lbs *

And this link has a 4 species chart...

*http://www.myoan.net/fishing/weight_calc.html*


Interesting stuff....I just carry a pretty accurate set of scales and leave the calculator at home.


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## markbxr400

Great stuff! Looks like the S. Carolina method is what I'm using.

Thanks.


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## firefighter14

Why not just use a scale?


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## FenderBender

firefighter14 said:


> Why not just use a scale?



Not everyone carries a scale while wade fishing, etc. Also many people choose not to stress a large fish that they plan on releasing by hanging it on a scale out of the water. Great post! Very informative. 


Sent from my iPhone using Tapatalk


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## Salt4Lifer

I think it was In-Fisherman that originally came up with the Weight = (length x length x length)/(number depending on fish species) I used to use the formula back in the freshwater day. I still remember largemouth bass being 1600.


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