Fishing numbers you can trace back to their source
Seven fishing calculators and two Upper Mississippi pool guides. Every number links to the agency, manual or paper it came from and shows the date we last checked it. If a figure cannot be sourced, the build fails and it does not ship.
Which tool do you need?
Four of the seven, and the ones people reach for most. Thefull calculator hub has the rest, including species-specific weight tools for walleye, channel catfish and largemouth bass.
Fish weight calculator
Length to weight for walleye, channel catfish and largemouth bass, using a separate published equation for each.
Mississippi River license finder
Which of the three states you need a license from, with the resident rule almost everyone gets backwards.
Line capacity calculator
How much braid actually fits a spool rated for monofilament, with a tolerance band because diameters are rounded.
Best fishing time calculator
Light, moon and pressure scored separately, each labelled with how strong the evidence behind it is.
Where do we actually fish?
Pools 8 and 9 of the Upper Mississippi, between La Crosse and Lynxville. Both guides carry a live water gauge reading, the bag limits that apply on that specific water, and the parts that catch people out — like the fact that crossing Lock and Dam 8 changes your walleye limit from four fish to six, and that a state line runs invisibly through the middle of Pool 9.
- Pool 8 fishing near Genoa, 23.3 miles and 20,800 acres from La Crosse down to the dam at Genoa.
- Pool 9 fishing near Lansing, 31.3 miles and 29,125 acres from Genoa down to Lynxville, across three states.
The river guide covers what applies across both: reciprocity between Wisconsin, Minnesota and Iowa, the two chapters of code that disagree with each other, and the 119-plus species the Wisconsin Department of Natural Resources counts in this water.
Why should you believe any of it?
Because you do not have to. Every page carrying factual claims ends with a source list: the full name of the publishing body, a link you can open, and the date a person last opened it. Nothing on this site says "studies show".
Behind that, three build gates run on every deployment. A figure without a publisher, an HTTPS link, a check date and a calibration grade fails to compile. A source more than 180 days past its last check stops the build. A page title or description outside its length window stops the build. Our fact-checking policy lists every condition, and the research methodology page is generated from the data files, so it cannot fall behind what we actually cite.
Questions people ask before they start
Are the calculators free?
All seven, with no account, no email and no app. The site is funded by advertising, and no ad unit is placed within a screen of a calculator result.
What makes this different from other fishing calculator sites?
Every figure names the body that published it, links to it and shows the date we last opened that link. The build refuses to deploy if any source is more than 180 days past its check date, so staleness is prevented by a script rather than by someone remembering.
Do the tools work without a signal?
Once a page has loaded, yes. All the arithmetic runs in your browser and none of it calls a server, so a calculator opened at the boat ramp keeps working out on the water.
Is this site the Big River Inn?
No. The domain previously belonged to a lodging business in Genoa, Wisconsin that no longer operates. Big River Fishing is an independent fishing resource with no connection to it and offers no lodging or hospitality services.