I just caught a largemouth that I believe is my new personal best, 21in long and 15.5in around. I didn’t have a scale with me so I’m wondering how to tell its weight with the two measurements I listed. I looked it up online and after entering the measurements the weights range from 5.6lb to 6.3lb so I’m not sure what one to go with. ( I ruined my phone after swamping my kayak so sadly I didn’t get a picture)

Thanks, August 

average it out

14 minutes ago, Rockhopper said:

average it out

Is there a specific formula you like to use?

Glenn has a fish weight calculator under the tools section.  I think you just plug in the numbers and it does the math for you.

5.6 + 6.3 /2?

Why not just call it a 21 incher since that’s the accurate measurement you already have.

The traditional formula commonly shown is: LxLxG/1200 which would put yours at 5.7 lbs. Others online will come up with a different number and formula including the BR weight calculator: https://www.bassresource.com/bassfishing/fishcalculator.html

 

It can be confusing, girth vs length.

I caught a a bass a few years ago that VA deems a citation yet only weighed 6.7 at 23" long.

Just enjoy the moment and release the fish and congratulations on a PB 👍

No picture no scale, I would average the two weights, then add a pound, or two.  Bigger is always better so why not give it a little fisherman's stretch.

Length to girth measuring must be accurate. Lay the fish flat and close the mouth then measure from the tip of the closed mouth down to the end of the flattened tail.

Girth is measure around the widest area with the dorsal fin down. 
The “average” body girth of a healthy LMB  is about 75% of the length. Some bass are heavy body mass that exceed 75% girth and can be up to 100% so girth is variable factor.

L x L x G div 1200 works for LMB body mass.

Tom
 

Nice. I'm 69" x 38" at 246 lbs, if that helps.😁

6 hours ago, August said:

Is there a specific formula you like to use?

Mathematically (elementary school level) add both numbers and divide by two. Because you’re only dealing with two numbers, the average is exactly the middle point between the two given numbers. 

It equates to 5.95 lbs. Once again from them old elementary school days, we round the figure. Therefore, the bass weighs approximately, 6 lbs. 👍😎

 

This figure is only as accurate as the fish calculator computes the final weight. Glenn’s calculator computed 6.7 lbs. I’d roll with that.
 

Congrats! That would be a beast in my neck of the woods. 

 

It'seasy - go here https://www.bassresource.com/bassfishing/fishcalculator.html