Accurately estimate the weight of your fish using this free Fish Weight Calculator by FishioHub. Whether you’re an angler recording your catch, a fish farmer tracking growth, or just curious about your aquarium fish, this calculator gives you a quick and reliable fish weight estimation from length and girth — in both pounds (lbs) and kilograms (kg).
Required Fields For Fish Weight Calculator:
- Fish Length (in cm or inches)
- Girth (in cm or inches)
- Select Species (Bass, Trout, Catfish, Generic Fish)
- [Calculate Button]
- Result: Approximate Fish Weight:
X lbs / X kg
H2: How the Fish Weight Calculator Works
The fish weight formula is based on standard fish length-to-weight conversions used in fisheries research. It is very simple,
Most commonly:
Weight (lbs) = (Length × Girth × Girth) / 800
Or in metric units:
Weight (kg) = (Length × Girth × Girth) / 9000
Tip: These formulas assume the fish has an average body condition. For best accuracy, measure both length and girth with a flexible measuring tape, keeping the fish straight and uncompressed.
Why Measure Fish Weight?
To Know the approximate weight of your catch or aquarium fish . By using fishiohub’s fish weight calculator by length you can find most accurate weight of a fish. You should measure fish weight for following:
- Comparing growth and health over time
- Complying with fishing regulations (minimum size limits)
- Estimating yield for aquaculture operations
- Logging records in fishing tournaments or personal diaries
- Avoiding harm — you can measure and release safely
Fish Weight Estimation Chart by Length (Example)
| Fish Length (inches) | Approx Weight (lbs) | Approx Weight (kg) |
|---|---|---|
| 10″ | 0.6 lbs | 0.27 kg |
| 15″ | 1.8 lbs | 0.82 kg |
| 20″ | 3.8 lbs | 1.72 kg |
| 25″ | 6.9 lbs | 3.13 kg |
| 30″ | 11.5 lbs | 5.22 kg |
(Values are approximate; actual weights may vary by species and condition.)
Fish Weight Formula by Species
Different species have unique body shapes, so their weight equations differ slightly. Below are some common formulas:
| Species | Formula (Imperial Units) | Notes |
|---|---|---|
| Bass | (Length × Girth²) / 800 | Most common formula for largemouth bass |
| Trout | (Length × Girth²) / 775 | Works well for rainbow and brown trout |
| Catfish | (Length × Girth²) / 900 | Slightly more elongated body shape |
| Generic Fish | (Length × Girth²) / 820 | Good average estimate |
Tips for Accurate Measurement
- Measure length from the snout to the tip of the tail (total length).
- Measure girth at the thickest part of the body.
- Always use a soft tape — not a ruler or stiff object.
- Avoid estimating visually; small errors in girth cause large weight differences.
- Record measurements immediately to avoid stress on live fish.
Convert Fish Weight Between Units
Our official fish weight calculator automatically converts between pounds and kilograms.
For manual conversion:
- 1 lb = 0.4536 kg
- 1 kg = 2.2046 lbs
So if your fish weighs 5 lbs, that’s roughly 2.27 kg.
Bookmark or Share :Fish Weight Calculator By Length
This official Fish Weight Calculator is designed for frequent use.
📌 Bookmark this page or share it with your fishing friends.
If you run a fishing blog or club, you can embed this calculator using a simple iframe — link back to FishioHub.com for the latest version.
Related Tools on FishioHub
FAQs
Q1: How accurate is the Fish Weight Calculator?
A: It gives a good approximation (within ±10%) for most species if you measure correctly. Accuracy may vary for unusually shaped fish.
Q2: Can I use this calculator for saltwater fish?
A: Yes. The general formula applies to both freshwater and saltwater fish, though larger species may need species-specific formulas.
Q3: What’s the difference between weight by length and by girth?
A: Length-only formulas give a rough estimate, while including girth significantly improves accuracy.
Q4: How do I measure girth safely?
A: Use a flexible tape around the thickest part of the fish while keeping it in a wet towel or cradle — to prevent injury before release.
Q5: Can I download or embed this tool?
A: Yes, you can embed it on your own fishing blog by copying the provided code (link back to FishioHub for credits).
🐟 Conclusion: Measure Accurate with FishioHub’s Fish Weight Calculator
Whether you’re an angler tracking your latest catch or an aquarist monitoring fish growth, the FishioHub Fish Weight Calculator makes it easy to estimate weight without harming your fish.
Simply measure, enter your values, and get accurate results in seconds.
This tool combines precision and convenience — ideal for both casual hobbyists and professional fisheries.
Explore more free FishioHub Tools like the Aquarium Volume Calculator and Salinity Converter to manage your aquatic world more effectively.
🎣 Start calculating now and make every measurement count!