🐟 Smallmouth Bass Weight Calculator
Estimate smallmouth bass weight from length & girth — imperial & metric results instantly
| Length (in) | Length (cm) | Est. Weight (lb) | Est. Weight (kg) | Avg Girth (in) | Classification |
|---|---|---|---|---|---|
| 10" | 25.4 cm | 0.54 lb | 0.24 kg | 6.7" | Sub-legal |
| 12" | 30.5 cm | 0.90 lb | 0.41 kg | 8.0" | Keeper Size |
| 13" | 33.0 cm | 1.15 lb | 0.52 kg | 8.7" | Keeper Size |
| 14" | 35.6 cm | 1.44 lb | 0.65 kg | 9.4" | Good Fish |
| 15" | 38.1 cm | 1.76 lb | 0.80 kg | 10.1" | Good Fish |
| 16" | 40.6 cm | 2.13 lb | 0.97 kg | 10.7" | Good Fish |
| 17" | 43.2 cm | 2.57 lb | 1.17 kg | 11.4" | Quality Fish |
| 18" | 45.7 cm | 3.06 lb | 1.39 kg | 12.1" | Quality Fish |
| 19" | 48.3 cm | 3.61 lb | 1.64 kg | 12.7" | Quality Fish |
| 20" | 50.8 cm | 4.23 lb | 1.92 kg | 13.4" | Trophy |
| 21" | 53.3 cm | 4.91 lb | 2.23 kg | 14.1" | Trophy |
| 22" | 55.9 cm | 5.67 lb | 2.57 kg | 14.7" | Big Trophy |
| 23" | 58.4 cm | 6.50 lb | 2.95 kg | 15.4" | Big Trophy |
| 24" | 61.0 cm | 7.42 lb | 3.37 kg | 16.1" | Monster |
| Condition Factor (K) | Rating | Multiplier Applied | Typical Habitat | Notes |
|---|---|---|---|---|
| 0.8 | Poor | x 0.8 | Stressed waters | Thin, elongated fish |
| 0.9 | Below Average | x 0.9 | Low-food rivers | Lean body condition |
| 1.0 | Average | x 1.0 | Typical rivers/lakes | Standard benchmark |
| 1.1 | Good | x 1.1 | Productive lakes | Well-fed, healthy fish |
| 1.2 | Excellent | x 1.2 | Premium reservoirs | Fat, deep-bodied fish |
| Formula | Equation | Result (18" / K=1.0) | Best Used For |
|---|---|---|---|
| Standard (L³/1600) | 18³ ÷ 1600 | 3.65 lb | Length-only quick estimate |
| Girth (LxG²/800) | (18 x 13²) ÷ 800 | 3.80 lb | Most accurate with girth |
| Preston (LxG²/900) | (18 x 13²) ÷ 900 | 3.38 lb | Conservative girth estimate |
| Anderson (L³/1500) | 18³ ÷ 1500 | 3.89 lb | Slightly heavier-bodied fish |
| Species | Avg Adult Weight | Trophy Weight | World Record | Formula Divisor |
|---|---|---|---|---|
| Smallmouth Bass | 1.5–3.5 lb (0.7–1.6 kg) | 5+ lb (2.3 kg) | 11 lb 15 oz (5.4 kg) | 1600 (L³) |
| Largemouth Bass | 2–5 lb (0.9–2.3 kg) | 8+ lb (3.6 kg) | 22 lb 4 oz (10.1 kg) | 1200 (L³) |
| Spotted Bass | 1–3 lb (0.5–1.4 kg) | 4+ lb (1.8 kg) | 10 lb 4 oz (4.7 kg) | 1400 (L³) |
| Striped Bass | 5–15 lb (2.3–6.8 kg) | 30+ lb (13.6 kg) | 81 lb 14 oz (37.1 kg) | 800 (LxG²) |
The smallmouth bass ranks between the most liked freshwater fishes, that belongs to the sunfish family. It has a body with olive or almost black colour marked by vertical brown strips, that commonly fades over time. The length of them ranges from 10 to 27 inches, while the weight reaches around 0.8 to 12 pounds.
Most of them live between 5 and 15 years.
Smallmouth Bass Size and Weight
The biggest recorded size for smallmouth bass is around 27 inches and 12 pounds. Although, in many waters for basses, the adults mostly reach only 2 to 3 pounds. Fish above 5 pounds happens fairly rarely in various regions.
For most caught fishes, the average weight sits between 1 and 4 pounds.
In the north of Ontario, typical smallmouth bass has weight of one to two pounds and length of around 15 or 16 inches. Fish of 18 inches deserves big praise, while one of 20 inches certainly counts as trophy. Well fed bass of 20 inches usually weigh between 4 and 5 pounds.
Fish of 7 to 10 years can pass 20 inches in length and pass 5 pounds in weight. Record fish above 10 pounds probably are much more old and gained form ideal conditions for growth.
smallmouth bass commonly weighs a bit more for a given length compared to largemouth bass. It makes sense, because they widely have more sturdy build. A bass of 18 inches normally outweighs his largemouth brother of same length quite noticeably.
One can use a simple formula to estimate the weight of smallmouth bass. Take the length, square it twice, then multiply by three, and later divide by 1600. The girth plays also a key role and can really alter the result.
To measure girth, wrap the tape around the thickest part of the fish body. The whole length goes from the tail fin to the muzzle. Tables about weights, that are based on measures of various fish species through the state New York, help to value weight only from length.
Some real catches show the varieties in weight. Smallmouth bass of 21.75 inches weighed exactly 5 pounds. Fish of 17 inches reached 3 pounds and 5 ounces.
A fisher caught a 22-inch sample at 5.3 pounds. One of 19 inches hit 4 pounds. On the other hand, slim bass of 24 inches weighed under 4 pounds, which shows, that the condition of the fish seriously matters.
State records help to understand the upper limit. In Maine, the state record for smallmouth bass is 8 pounds. The record of Oregon stays at 7 pounds.
Washington state accepted a 9.32-pound sample as new record. The smallmouth bass comes from the upper and middle basin of the Mississippi River, the Saint Lawrence River and the Great Lakes, as well as from the upperHudson River basin.
