If you don't have a scale and just hooked into the big one, no worries. With the MyNature Fish Weight Calculator you only need to measure the length and girth of your catch to get an estimate that's within 10% of the fish's actual weight. The weight calculator couldn't be easier to use, simply select the species you caught on the wheel, enter the two measurements girth and length and hit calculate, it's that easy. We also included a pop-up screen with fractions of an inch conversions so you can spend more time fishing and not doing math. Good luck on the water!!