The length to weight conversion chart below provides a close approximation of the weight of Atlantic and Pacific halibut between 18 and 100 inches based on overall length.
The halibut length to weight conversion chart below provides live and dressed weight estimates based on the length of a halibut in inches or centimeters.
| Length | Live Weight (lbs) | Dressed Weight (lbs) | Length | Live Weight (lbs) | Dressed Weight (lbs) |
|---|---|---|---|---|---|
| 18in (45cm) | 2.2 | 1.6 | 57in (145cm) | 92.2 | 69.3 |
| 20in (50cm) | 3.1 | 2.3 | 58in (147cm) | 97.5 | 73.3 |
| 22in (55cm) | 4.2 | 3.2 | 59in (150cm) | 103.1 | 77.5 |
| 24in (61cm) | 5.6 | 4.2 | 60in (152cm) | 108.9 | 81.8 |
| 25in (63cm) | 6.4 | 4.8 | 61in (155cm) | 114.8 | 86.3 |
| 26in (66cm) | 7.2 | 5.4 | 62in (158cm) | 121.1 | 91 |
| 27in (68cm) | 8.2 | 6.2 | 63in (160cm) | 127.5 | 95.8 |
| 28in (71cm) | 9.2 | 6.9 | 64in (163cm) | 134.2 | 100.9 |
| 29in (74cm) | 10.3 | 7.8 | 65in (165cm) | 141.1 | 106.1 |
| 30in (76cm) | 11.5 | 8.7 | 66in (168cm) | 148.2 | 111.5 |
| 31in (79cm) | 12.8 | 9.6 | 67in (170cm) | 155.6 | 117 |
| 32in (81.cm) | 14.2 | 10.7 | 68in (173cm) | 163.3 | 122.8 |
| 33in (84cm) | 15.7 | 11.8 | 69in (175cm) | 171.2 | 128.7 |
| 34in (86cm) | 17.3 | 13 | 70in (178cm) | 179.4 | 134.9 |
| 35in (89cm) | 19 | 14.3 | 71in (180cm) | 187.8 | 141.2 |
| 36in (91cm) | 20.8 | 15.6 | 72in (183cm) | 196.5 | 147.7 |
| 37in (94cm) | 22.7 | 17.1 | 73in (185cm) | 205.5 | 154.5 |
| 38in (97cm) | 24.8 | 18.6 | 74in (188cm) | 214.8 | 161.5 |
| 39in (99cm) | 27 | 20.3 | 75in (191cm) | 224.3 | 168.6 |
| 40in (102cm) | 29.3 | 22 | 76in (193cm) | 234.1 | 176 |
| 41in (104cm) | 31.7 | 23.8 | 77in (196cm) | 244.3 | 183.7 |
| 42in (106.7cm) | 34.3 | 25.8 | 78in (198cm) | 254.7 | 191.5 |
| 43in (109cm) | 37 | 27.8 | 79in (201cm) | 265.4 | 199.5 |
| 44in (111.8cm) | 39.9 | 30 | 80in (203cm) | 276.5 | 207.9 |
| 45in (114.3cm) | 42.8 | 32.2 | 81in (206cm) | 287.8 | 216.4 |
| 46in (116.8cm) | 46 | 34.6 | 82in (208cm) | 299.5 | 225.2 |
| 47in (119.4cm) | 49.3 | 37.1 | 83in (211cm) | 311.5 | 234.2 |
| 48in (121.9cm) | 52.7 | 39.7 | 84in (213cm) | 323.8 | 243.4 |
| 49in (124.5cm) | 56.5 | 42.5 | 86in (218cm) | 349.5 | 262.8 |
| 50in (127cm) | 60.3 | 45.3 | 88in (224cm) | 376.5 | 283.1 |
| 51in (129.5cm) | 64.3 | 48.3 | 90in (229cm) | 404.9 | 304.4 |
| 52in (132.1cm) | 68.5 | 51.5 | 92in (234cm) | 434.8 | 326.9 |
| 53in (134.6cm) | 72.8 | 54.8 | 94in (239cm) | 466.2 | 350.5 |
| 54in (137.2cm) | 77.4 | 58.2 | 96in (244cm) | 499.1 | 375.3 |
| 55in (139.7cm) | 82.1 | 61.7 | 98in (249cm) | 533.6 | 401.2 |
| 56in (142cm) | 87 | 65.5 | 100in (254cm) | 569.7 | 428.4 |
The length of a halibut can also be estimated using the following conversion formulas. The most accurate formula for estimating a halibut’s weight incorporates girth. However, accurate girth measurements can be difficult to obtan for halibut—especially larger specimens. When girth isn’t available, you can use the length only formula to estimate a halibut’s weight.
- (length x girth x girth)/625
- (length x length x length)/2400
The length formula listed above—(length x length x length)/2400—does not incorporate girth. It isn’t the more accurate estimate, but it’s the easiest to obtain. Measure the total length (TL) of the halibut, cube the length, then divide by 2400—your divisor or “shape” factor.
As halibut mature, their shape changes and they tend to become bulkier. When using the length formula without girth, you should adjust the divisor down for larger halibut to get a more accurate weight estimate. 2400 is the best shape factor to use for smaller halibut between 18 and 30 inches. The following chart provides the divisor that will provide the most accurate weight estimate based on length categories.
| Halibut Length | Length to Weight Formula |
|---|---|
| 18 - 30 inches | (length x length x length)/2400 |
| 31-40 inches | (length x length x length)/2200 |
| 41-50 inches | (length x length x length)/2100 |
| 51-60 inches | (length x length x length)/2000 |
| 61-70 inches | (length x length x length)/1900 |
| 71-80 inches | (length x length x length)/1850 |
| 81-90 inches | (length x length x length)/1800 |
| 91-100 inches | (length x length x length)/1750 |
How to Measure Halibut Length and Girth
Measure halibut length using a flexible tape measure.
For halibut length, measure from the tip of the lower jaw with the mouth closed, to the end of the middle of the tail passing the tape in a straight line over the pectoral fin.
For girth, measure the circumference of the halibut at the thickest point of the midsection.
