About Fishing Toolbox

Fishing Toolbox is built by a small team of mathematically-minded anglers — the kind of people who, instead of guessing, would rather run the numbers. We got tired of doing the same quick calculations by hand at the boat ramp: estimating a fish’s weight, dialing in drag, working out how deep a lure was running. So we put the math we actually use into one free, no-login place that works on your phone right at the water.

Everything here is free, with no sign-up and no app to download. Our calculators are built on established, widely-used angling formulas, and our guides explain the how and why behind them so you can fish smarter, not just harder.

What you’ll find here

A fish weight estimator, reel line capacity calculator, drag-setting tool, trolling depth estimator, a sunrise and sunset bite-window finder, a water-temperature species guide, and handy unit converters — plus a growing library of how-to guides and species length-to-weight charts.

We’re anglers first and number-crunchers second (okay, maybe it’s a tie). If a number ever looks off, or you’d like to see a tool added, we’d love to hear from you on our contact page. Tight lines.