Fish Weight Calculation Formulas

Weight estimation formulas based on empirical data and research

About These Formulas

These formulas have been developed through extensive empirical data and research. While they typically provide good results, please note that they are estimates and actual weights may vary depending on various factors including the fish's condition and season.

Formula Types

Length × Girth² Formula

Weight = (Length × Girth × Girth) / Factor

  • • Trout (750)
  • • Walleye (750)
  • • Pike (900)
  • • Catfish (850)
  • • Carp (800)
  • • Bluegill (1,200)
  • • Bonefish (900)
  • • Snook (900)
  • • Redfish (900)
  • • Bluefish (900)
  • • Salmon (800)
  • • Mackerel (900)

Length² × Girth Formula

Weight = (Length × Length × Girth) / Factor

  • • Bass (1,200)

Length³ Formula

Weight = (Length × Length × Length) / Factor

  • • Sunfish (1,200)
  • • Gar (2,700)
  • • Crappie (1,600)
  • • Sheepshead (1,200)
  • • Flounder (2,500)

Important Notes

  • 1. All measurements must be in inches. The app will convert from cm to inches if cm is selected.
  • 2. Measure girth at the widest point of the fish
  • 3. Length should be total length (tip of snout to tip of tail)
  • 4. Results are estimates and may vary based on fish condition and season