How much does a smallmouth bass weigh?
Upload a photo of your catch, or use the tools below, to estimate its weight.
About the smallmouth bass
Typical adult length: 8–18 in (about 0.4–4.3 lb)
- Lifespan
- Typically lives 9 to 14 years.
- Habitat
- Prefers clear, cooler water with rocky or gravel bottoms in lakes and rivers.
- Diet
- Feeds mainly on crawfish, minnows, and aquatic insects.
- Baits & techniques
- Tube jigs, crawfish imitations, and small crankbaits worked along rocky structure are effective.
- Best season
- Late spring through early fall, especially once water temperatures warm past the spawn.
- Best time of day
- Dawn and dusk are usually the most active feeding windows.
- Pound for pound, smallmouth bass are known as one of the hardest-fighting freshwater fish.
- They're more sensitive to water clarity and temperature than largemouth bass, generally preferring cleaner water.
- Smallmouth often relate closely to current and structure in rivers rather than open water.
Smallmouth Bass length-to-weight chart
10 inches up to record size (27 in), using the standard length-to-weight formula for this species.
| Length (in) | Estimated weight (lb) |
|---|---|
| 10 | 0.7 |
| 12 | 1.3 |
| 14 | 2.0 |
| 16 | 3.0 |
| 18 | 4.3 |
| 20 | 5.9 |
| 22 | 7.9 |
| 24 | 10.2 |
| 26 | 13.0 |
| 27 | 14.6 |
Estimating weight without a scale
Length-to-weight formulas like the one above assume a typical smallmouth bass 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.