Largemouth Bass Relative Weight Index Chart

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 Length (in.)    110%  Standard Weight 100%  95%  90%  85%  80%  75% 
10    0.55  0.50  0.47  0.45  0.43  0.40  0.37 
10.5    0.67  0.61  0.58  0.55  0.52  0.49  0.46 
11    0.75  0.68  0.65  0.61  0.58  0.54  0.51 
11.5    0.86  0.78  0.74  0.70  0.66  0.62  0.58 
12    0.99  0.90  0.85  0.81  0.76  0.72  0.67 
12.5    1.12  1.02  0.97  0.92  0.87  0.81  0.76 
13    1.28  1.16  1.10  1.04  0.98  0.93  0.87 
13.5    1.44  1.31  1.24  1.18  1.11  1.05  0.98 
14    1.62  1.47  1.39  1.32  1.25  1.17  1.10 
14.5    1.80  1.64  1.56  1.48  1.39  1.31  1.23 
15    2.01  1.83  1.74  1.65  1.56  1.46  1.37 
15.5    2.23  2.03  1.93  1.83  1.72  1.62  1.52 
16    2.47  2.25  2.14  2.02  1.91  1.80  1.69 
16.5    2.73  2.48  2.35  2.23  2.11  1.98  1.86 
17    3.00  2.73  2.59  2.45  2.32  2.18  2.05 
17.5    3.30  3.00  2.85  2.70  2.55  2.40  2.25 
18    3.61  3.28  3.11  2.95  2.79  2.62  2.46 
18.5    3.93  3.58  3.40  3.22  3.04  2.86  2.68 
19    4.28  3.89  3.69  3.50  3.30  3.11  2.91 
19.5    4.65  4.22  4.00  3.79  359  3..38  3.17 
20    5.04  4.59  4.36  4.13  3.90  3.67  3.44 
20.5    5.45  4.96  4.71  4.46  4.21  3.96  3.72 
21    5.89  5.35  5.09  4.82  4.55  4.28  4.02 
21.5    6.35  5.78  5.49  5.20  4.91  4.62  4.33 
22    6.83  6.21  5.90  5.59  5.28  4.97  4.66 
22.5    7.34  6.67  6.34  6.01  5.67  5.34  5.01 
23    7.88  7.16  6.81  6.45  6.09  5.73  5.37 
23.5    8.43  7.66  7.28  6.90  6.51  6.13  5.75 
24    9.02  8.20  7.79  7.38  6.97  6.56  6.15 
24.5    9.64  8.76  8.32  7.89  7.45  7.01  6.57 
 
 

Measure fish from tip of nose with mouth closed to the end of the tail (make sure to “pinch” the tail). To estimate weight of a specific bass, weigh in tenths of pounds and measure in inches to nearest ½ inch and then using the table above look up the relative weight of the bass length. For example: a bass was caught measuring 16” and weighed 2 lbs. Looking at the chart this particular bass has a relative weight of approximately 90%. To get the exact relative weight of a bass, use the standard weight column from the table above to find the standard weight of the bass caught. Divide the actual weight of the bass caught by the standard weight and multiply by 100. This will give you the relative weight of the bass caught. Example: a 20.5” bass was caught weighing 4.2 pounds. Looking at the table above, the standard weight for a 20.5” is 4.96 pounds. 4.2/4.96 = 0.846 * 100 = 85%.