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How to Estimate the Weight of a Fish

Fishing the Salmon River, Polaski, NY

Photo Credit
Mary Jaeger
Catherine Boeckmann
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No more fishing stories! When it comes to fishing, the best part is talking about how big your fish is! However, if you are a catch-and-release fisherman, sometimes you cannot accurately portray its size. Now you can! Here’s how to estimate the weight of a fish.

  • Measure the fish from the tip of its nose to the tip of its tail.
  • Then measure its girth at the thickest portion of its midsection.

Weight of a fat-bodied fish
(bass, salmon)
(length x girth x girth)/800

Read Next

Weight of a slender fish
(trout, northern pike)
(length x girth x girth)/900

Example:
If a fish is 20 inches long and has a 12–inch girth, its estimated weight is
(20 x 12 x 12)/900
2,880/900=3.2 pounds
 

What is the biggest fish you have ever caught? Tell us all about it in the comments below!

Fishing
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
 

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Comments

Victor Campbell (not verified)

7 months 2 weeks ago

I caught a 24 1/2” largemouth bass its girth was 19 1/2”. Caught at Lake Bacharach, Mexico. On a scale it was 10 lb 7 oz

Kstar (not verified)

4 years 8 months ago

It can be measured in a any weighting machine

john f (not verified)

9 years 9 months ago

that's why they call it fishing not catching.

chinzete David (not verified)

10 years 4 months ago

Please help me with formula to estimate robusta fish weight.

Thank you

Mr Rooster (not verified)

11 years 7 months ago

Settle down boys, it's just a fish!

Tboner (not verified)

11 years 7 months ago

I will tell you where I caught my fish. There is luck and skill to catching fish and there"s plenty for all. Don't be a smart ass.

steve spees (not verified)

11 years 9 months ago

This is the fixed version of the 1st. Sorry could you delete the 1st?
Hi
You know how everybody always ask you where you caught it,and you really don't want to say.

I always say in the mouth or in the water,lol.

Sneaky,huh!