Bass
Largemouth bass
Micropterus salmoides.
Length to weight chart, typical size by age, and how to photograph a largemouth bass so fishline measures it well.
- Typical top length
- 24 in
- about 9.2 lb
- An 18 inch fish
- 3.6 lb
- 3 lb 10 oz
- Age at 18 inches
- about 5 years
- rough, varies by water
- Growth levels off
- about age 12
- gains slow to a crawl after
Largemouth bass length to weight chart
Estimated weight for a largemouth bass in average shape at each length, from the formula W = L^3.2 / 2,850 (W in pounds, L in inches). It is the same relationship fishline uses when it measures a largemouth bass from a photo.
| Length | Weight | Rough age |
|---|---|---|
| 8 in | 0.27 lb | 1 to 2 years |
| 10 in | 0.56 lb | about 2 years |
| 12 in | 1.0 lb | 2 to 3 years |
| 14 in | 1.6 lb | about 3 years |
| 16 in | 2.5 lb | about 4 years |
| 18 in | 3.6 lb | about 5 years |
| 20 in | 5.1 lb | 6 to 7 years |
| 22 in | 6.9 lb | about 9 years |
| 24 in | 9.2 lb | 12+ years |
| 26 in | 11.8 lb | 12+ years |
Total length, nose to the tip of the pinched tail. Weights are for a largemouth bass in average shape. A fat fish, like a female before the spawn, weighs more and a thin one less, which a girth measurement picks up. Rows past 24 inches are bigger than typical for the species.
Size by age
fishline's growth model puts a typical largemouth bass at around 24 inches when fully grown, with most of its growth done by about age 12. Younger fish add length fast; older fish mostly add weight.
Age from length is rough. Fish in warm water with plenty to eat grow faster than this, and fish in cold or crowded water grow slower. For a quick estimate from any length, use the fish age calculator.
| Age | Length | Weight |
|---|---|---|
| 1 year | 5.9 in | 0.10 lb |
| 2 years | 10.3 in | 0.61 lb |
| 3 years | 13.6 in | 1.5 lb |
| 4 years | 16.2 in | 2.6 lb |
| 5 years | 18.1 in | 3.7 lb |
| 6 years | 19.5 in | 4.7 lb |
| 8 years | 21.4 in | 6.4 lb |
| 10 years | 22.5 in | 7.5 lb |
| 12 years | 23.2 in | 8.2 lb |
From a von Bertalanffy growth curve. Fish in warm, food-rich water grow faster than this and fish in cold or crowded water grow slower, so treat every row as a rough middle.
Weigh your largemouth bass
Enter the length, and the girth if you taped it, for an estimate on your fish.
Photo tips for largemouth bass
fishline reads length from the photo using whatever is in frame for scale, so a clean, side-on shot gives the tightest number.
- 1Hold the fish side-on with your arms in close. Lip it with one hand, put the other under the belly, and keep it level with your chest instead of pushing it toward the lens.
- 2Get the whole fish in the frame, nose to tail, with the tail pinched closed the way you would on a bump board.
- 3Leave your hand on the fish where the camera can see it. fishline uses an adult hand for scale, and a bump board or tape in the shot is even better.
Or skip the tape. Snap a photo and fishline measures it.
Species, length and weight from one photo. 5 free measurements every month.