How much does a blue catfish weigh?
Upload a photo of your catch, or use the tools below, to estimate its weight.
About the blue catfish
Typical adult length: 15–40 in (about 1.5–29.1 lb)
- Lifespan
- Can live 20 years or more.
- Habitat
- Prefers large rivers and reservoirs with strong current and deep channels.
- Diet
- Feeds on fish, crustaceans, and other aquatic life, becoming increasingly predatory as it grows.
- Baits & techniques
- Fresh cut bait, especially shad, fished on the bottom in current seams is a proven approach.
- Best season
- Summer and fall tend to produce the most consistent big-fish action.
- Best time of day
- Blue catfish can feed throughout the day, though low light often improves activity.
- Blue catfish are one of the largest freshwater fish species in North America.
- They were introduced outside their native range into several major East Coast river systems.
- Blue catfish can be distinguished from channel catfish by their straight-edged anal fin.
Blue Catfish length-to-weight chart
10 inches up to record size (58 in), using the standard length-to-weight formula for this species.
| Length (in) | Estimated weight (lb) |
|---|---|
| 10 | 0.5 |
| 12 | 0.8 |
| 14 | 1.2 |
| 16 | 1.9 |
| 18 | 2.7 |
| 20 | 3.6 |
| 22 | 4.8 |
| 24 | 6.3 |
| 26 | 8.0 |
| 28 | 10.0 |
| 30 | 12.3 |
| 32 | 14.9 |
| 34 | 17.9 |
| 36 | 21.2 |
| 38 | 24.9 |
| 40 | 29.1 |
| 42 | 33.7 |
| 44 | 38.7 |
| 46 | 44.2 |
| 48 | 50.3 |
| 50 | 56.8 |
| 52 | 63.9 |
| 54 | 71.6 |
| 56 | 79.8 |
| 58 | 88.7 |
Estimating weight without a scale
Length-to-weight formulas like the one above assume a typical blue catfish shape for a given length - fisheries biologists call this the cube law. Real fish vary: a well-fed fish ahead of spawning season can weigh noticeably more than a lean fish of the same length, and body shape varies fish to fish.
Adding girth (the distance around the fish at its widest point) meaningfully improves the estimate, because it captures how deep-bodied this particular fish actually is instead of assuming average proportions for the species - use the calculator above and fill in girth if you can measure it.
Either way, treat the result as a solid estimate, not a certified weight - see our terms for why these numbers shouldn't be used for tournaments, regulations, or sales.