Free Trailer Tongue Weight calculator with clear step-by-step results.
Tongue weight should be roughly 10% of loaded trailer mass - too little and the trailer will snake at speed, too much and it unloads the tow vehicle's front axle. The adjustment figure tells you how much load to move, and the lever arm converts that into how far cargo needs to shift.
Target tongue weight
Target = loaded trailer mass x target percentage
Cargo shift
Moving mass m by distance d changes tongue weight by m x d / axle-to-coupling distance
Trailer loading and tongue weight are safety-critical and legally regulated. Weigh the coupling load, respect the towball and vehicle vertical load limits, and follow the trailer manufacturer's loading instructions.
The trailer becomes directionally unstable and can begin to oscillate, or snake, at speed. Recovery is difficult and jackknifing is a real risk.
No. The vertical load rating is an independent limit set by the towbar and vehicle, and exceeding it is both unsafe and illegal.