How to Measure Trailer Tongue Weight: Scales & DIY Methods
Knowing your exact tongue weight prevents highway sway accidents, illegal axle overloads, and equipment damage. Here is the engineering breakdown of the four proven ways to weigh a trailer and measure tongue weight.
Hitch weight and tongue weight are the exact same measurement when referring to conventional bumper-pull trailers. The terms are used interchangeably by automakers and hitch manufacturers to describe the downward vertical load resting on the hitch ball. In commercial and fifth-wheel towing, this downward force is termed pin weight.
Moment-arm leverage: Using a 3:1 ratio multiplier allows a 300 lb scale to weigh up to a 900 lb tongue.
Method 1: The DIY Bathroom Scale Lever (Most Popular)
If your tongue weight exceeds your bathroom scale’s 300 lb limit, a 2x4 wood beam divides the load using Archimedes' law of the lever:
- Lay a 36-inch 2x4 horizontally across two steel pipes on level ground.
- Place one pipe on your bathroom scale and the other on a wooden support block of equal height.
- Position your trailer tongue jack exactly 12 inches from the support block pipe.
- The Math: Because the total span (36″) is 3 times the jack distance (12″), your lever ratio is 3:1. Multiply the scale reading by 3.
Run your exact board lengths in our Interactive Bathroom Scale Lever Calculator →
Method 2: Commercial CAT Scale (How to Weigh a Trailer)
Available at major highway truck stops. CAT scales use 3 separate platform pads to calculate tongue weight by subtraction:
- Weigh 1 (Truck + Trailer Attached): Record Steer Axle (Pad 1), Drive Axle (Pad 2), and Trailer Axles (Pad 3).
- Weigh 2 (Truck Alone): Park the trailer, pull the truck onto the scale alone, and record Steer Axle and Drive Axle.
- The Math:
Tongue Weight = (Weigh 1 Truck Total) − (Weigh 2 Truck Total)
Decode your CAT scale ticket numbers instantly with our CAT Scale 3-Pass Calculator →
Trailer Tongue Weight Scale Buyer’s Comparison
If you tow regularly, dedicated commercial scales eliminate the need for wooden lever setups:
| Measurement Tool | Max Capacity | Accuracy | Typical Cost | Best Suited For |
|---|---|---|---|---|
| DIY 2×4 Bathroom Scale Lever | Up to 900–1,200 lbs | ±3% to 5% | Free – $20 | Home driveway verification, occasional towers |
| Sherline Hydraulic Tongue Scale | 1,000 – 5,000 lbs | ±1% to 2% | $140 – $180 | Serious RVers, boaters, equipment haulers |
| Weigh Safe Built-in Hitch Gauge | 1,500 – 2,200 lbs TW | ±1% to 2% | $220 – $320 | Continuous real-time measurement while towing |
| Certified Highway CAT Scale | 100,000+ lbs | ±0.1% (Legal for Trade) | $12.50 / weigh | Annual pre-season loaded camper check |
Compare Your Numbers Against Official Standards
Check our Master Towing Safety Calculator, view the SAE J2807 Percentage Matrix, check your truck payload with the Payload Capacity Sizer, or check our Weight Distribution Hitch Sizer.