Calculator
Tiny house weight budget
Storage, water and a full kitchen all add pounds, and a house on a trailer has a fixed limit. Enter the numbers you know to see what is left. It is for planning only. The result updates as you type and stays on your device.
12,407 lb loaded (89 percent of the rating)
Worked example (shown when scripts are off): 10,500 lb empty plus 1,500 lb of belongings, plus 20 gallons of water at about 167 lb, plus 40 lb of propane and 200 lb of other items, is about 12,407 lb against a 14,000 lb rating.
Before you decide
A scale beats a calculator. The empty weight on a brochure is often an estimate, so weigh the finished and loaded house at a certified scale, and check your tow vehicle's own ratings before you tow.
The rule in plain words
A trailer has a gross vehicle weight rating, or GVWR, printed on its label. That is the most the trailer and everything on it should weigh together. The loaded weight is the empty weight plus everything you add. The room that is left is the rating minus the loaded weight, and if it goes negative, you are over the rating. This tool also warns when you are within 10 percent of it, because real loads are nearly always heavier than a list.
The formula
- Water weight is gallons times 8.34 pounds, the weight of a US gallon of fresh water.
- Loaded weight is empty weight plus belongings, plus water, plus propane, plus anything else.
- Remaining is the rating minus the loaded weight. Percent used is loaded weight divided by the rating.
- Tongue weight guide is 10 to 15 percent of the loaded weight.
For example, 20 gallons of water is about 167 pounds, which is more than many people guess. Forty gallons is over 330 pounds. If you plan to carry water, count it.
Why tongue weight matters
Tongue weight is the downward force the trailer puts on the hitch. Published towing guidance for conventional trailers gives 10 to 15 percent of trailer weight as the usual target. Too little can let the trailer sway, and too much can overload the back of the tow vehicle and lighten the steering. Heavy items belong low and close to the axles, not high in a loft or at the far end. Our storage guide covers placing weight inside the house.
What it does not cover
It does not check the tow vehicle, its hitch, or the weight on each axle, and each of those has its own limit that can be lower than the trailer's. It also does not cover a house on a foundation, where weight is a structural question for a designer or engineer. If you are over or close to the rating, talk to the trailer builder or a qualified professional rather than trusting the arithmetic.
Where this comes from
We checked published towing guidance that gives 10 to 15 percent of trailer weight as the usual tongue weight for conventional bumper-pull trailers, and that tongue weight counts against the tow vehicle's own ratings. The weight of water is a standard physical value. The 90 percent warning level is our own planning margin, not a regulation. This is general information, not engineering or legal advice, and towing rules vary by place.