🐟 Flathead Catfish Weight Calculator
Estimate flathead catfish weight from length & girth — instant imperial & metric results
| Length (in) | Length (cm) | Est. Weight (lb) | Est. Weight (kg) | Avg Girth (in) | Classification |
|---|---|---|---|---|---|
| 15 | 38 | 2–3 | 0.9–1.4 | 9 | Juvenile |
| 18 | 46 | 3–5 | 1.4–2.3 | 11 | Small |
| 22 | 56 | 5–8 | 2.3–3.6 | 13 | Small |
| 26 | 66 | 8–12 | 3.6–5.4 | 15 | Average |
| 30 | 76 | 12–18 | 5.4–8.2 | 17 | Average |
| 34 | 86 | 18–27 | 8.2–12.2 | 20 | Above Average |
| 38 | 97 | 27–38 | 12.2–17.2 | 22 | Quality |
| 42 | 107 | 38–52 | 17.2–23.6 | 25 | Trophy |
| 46 | 117 | 52–68 | 23.6–30.8 | 27 | Trophy |
| 50 | 127 | 68–88 | 30.8–39.9 | 30 | Monster |
| 54 | 137 | 88–110 | 39.9–49.9 | 32 | Monster |
| 58+ | 147+ | 110–123+ | 49.9–55.8+ | 34+ | World Class |
| Species | Typical Weight | Max Weight | Formula Divisor | Body Shape |
|---|---|---|---|---|
| Flathead Catfish | 5–20 lb | 123 lb | 800 | Elongated, flat head |
| Blue Catfish | 3–30 lb | 143 lb | 800 | Cylindrical, forked tail |
| Channel Catfish | 1–10 lb | 58 lb | 900 | Slender, spotted |
| White Catfish | 0.5–3 lb | 22 lb | 900 | Stout, rounded |
| Bullhead (Yellow) | 0.5–2 lb | 4 lb | 950 | Compact, rounded |
| Fish Weight | Rod Power | Line Strength | Hook Size | Leader Strength |
|---|---|---|---|---|
| Under 10 lb | Medium-Heavy | 17–30 lb mono | 5/0–6/0 | 30 lb |
| 10–25 lb | Heavy | 30–50 lb mono | 7/0–8/0 | 50 lb |
| 25–50 lb | Heavy–XH | 50–80 lb braid | 8/0–10/0 | 80 lb |
| 50–80 lb | Extra Heavy | 80–100 lb braid | 10/0–12/0 | 100 lb |
| 80+ lb | Extra Heavy | 100–130 lb braid | 12/0+ | 130 lb |
Catfish come in various species, and their weight changes a lot according to the kind. Channel catfish normally has between two and four pounds and it reaches at least 12 inches. In 1964 one caught in South Carolina a record channel catfish of 58 pounds.
Blue catfish clearly beats that. It can reach up to 170 centimeters long and 143 pounds of weight. Some blue catfish pass even 100 pounds.
Catfish Sizes and How to Estimate Their Weight
In some rivers fishers spend hours to catch blue catfish, that weighs from five to almost 20 pounds.
Around the world there are even bigger catfish. One knows that some pass 2.5 meters long and 100 kilos of weight, although species more than 2 meters long are rare. In north Thailand one caught an huge Mekong catfish of incredible 646 pounds.
One of them, shown in a photograph, was estimated at 150 to 160 kilos, so around 330 to 352 pounds.
Here comes the funny part. There really is a way to estimate the weight of catfish without using a scale. The simple method works like this: first multiply the girth of the fish, then multiply that by the length and divide the result by 800.
For instance, for catfish long 49 inches with 32-inch girth, the calculation gives around 62.72 pounds. Another version divides buy 700 instead of 800, so the numbers a bit differ.
For bass and catfish together, another method uses the length squared divided by 1600. Also charts help to estimate weight. According to one of them, a 36-inch blue catfish weighs typical around 23.2 pounds.
A 32-inch one should have around 20.5 pounds. Fish long between 30.5 and 32 inches was measured at 14 to 16 pounds, while slimmer species arrive at around 12 pounds.
Little catfish are very common. On simple line with little hook, channel catfish averages around 2.5 pounds. One considers 2 to 4-pound channel catfish well edible.
In fly fishing the biggest caught catfish weighed eight pounds, while five-pound ones are quite usual. One fisher managed to catch a seven-pound and three-ounce catfish with a fly rod. Catfish more than 15 inches long give strong resistance on a 6-weight rod.
To get precise weights, a good step is to buy a reliable scale and start to note length, girth and weight for every fish. Some fishersweigh the catch in a net, then subtract for the final weight.
