Yeah, you can use the shade-tree mechanic method Ken linked to, or you can do it right with a Sherline Trailer Tongue Weight Scale - 2,000-lb Capacity. I got mine from eTrailer.com for about $130 delivered.
Sherline Trailer Tongue Weight Scale - 2,000-lb Capacity Sherline Tools 5780
Reese/Drawtite sells the same thing for a lot more money. In fact, the Drawtite and Sherline both have that "5780" in the part number.
Draw-Tite Part No. 5780
Grumpy ole man with over 50 years towing experience. Now my heaviest trailer is a 7,000-pound enclosed cargo trailer, RV is a 5,600 pound Skyline Nomad Joey 196S, and my tow vehicle is a 2012 F-150 EcoBoost SuperCrew.