How do you estimate a fish's weight without a scale?

Measure total length and girth in inches, then use Weight (lb) = (Length x Girth squared) / 800 for bass-shaped fish, or /900 for slimmer fish like trout, walleye and pike. With an accurate girth this is usually within 5 to 10 percent.

How deep does lead core line run?

A common rule of thumb is about 5 feet of depth per color at roughly 2 mph. Trolling slower runs deeper and trolling faster runs shallower. Thinner lead core sinks more per color.

What drag setting should I use?

A good starting point is one quarter to one third of your line's breaking strength. For 20 lb line that is about 5 to 6.6 lb. Set it with a scale and lighten it for light leaders or hard-fighting fish.

What water temperature is best for fishing?

Every species feeds best in a preferred band, for example largemouth bass around 65 to 80 F and trout around 52 to 64 F. The Water Temp guide shows which species are most active at your current water temperature.

When is the best time of day to fish?

Dawn and dusk are prime feeding windows for most species. The Sunrise/Sunset tool gives exact sun times and the best low-light windows for your location and date.

Free Fishing Calculators & Tools

A free, no-login toolbox for anglers. Estimate a fish’s weight, set your drag, work out trolling depth, find the best bite times, match line capacity, and convert the numbers you actually use on the water. Everything runs right in your browser, on your phone or desktop.