Why truck length tells you almost nothing
A rental fleet is advertised by box length, but the number that decides whether your sofa gets on board is the box volume, and volume does not scale the way length suggests. A 26 ft truck is 1.7 times the length of a 15 ft truck and holds roughly 2.1 times the volume, because the longer trucks are also taller and wider inside. That is why "my friend moved a three-bed house in a 15-footer" is such unreliable advice, and why the honest way to size a truck is to build the load in cubic feet first and match a vehicle to it afterwards.
Professional estimators have done exactly this for decades using a cube sheet: a list of household items with a cubic-foot figure against each, totalled to give the volume of the shipment, which is then converted to a weight for tariff purposes. This calculator is a compressed cube sheet. Rather than making you price 200 line items, it uses a per-room allowance to stand in for furniture — the part of a household that varies least between homes of the same size — and asks you to count the two things that genuinely vary: boxes and appliances.
The result is a volume, a recommended truck, and the number a lot of people forget to ask for: how many journeys a smaller truck would cost you. A 10 ft truck at half the daily rate is not half the price if it turns one 25-mile run into five legs of driving and a whole extra day of loading.
The four numbers that build the total
Furniture, by the room. Multiply your furnished rooms by a volume allowance. The mover's rule of thumb is 150–200 cu ft per furnished room, and the default here of 175 sits in the middle of it. Treat it as a dial, not a constant: a bedroom with a bed, a wardrobe and a chest is nearer 150, while a dining room with a table, eight chairs and a dresser can pass 250. Rooms with no furniture do not count at all, which is why a large but sparsely furnished house can travel in a smaller truck than a crowded flat.
Boxes, by the count. Cartons are the one item you can count exactly, and they are sold in standard volumes: the small book box is 1.5 cu ft, the medium is 18 × 18 × 16 in — exactly 3.0 cu ft — the large is 4.5 cu ft and the extra-large linen carton is 6.0 cu ft. Multiply your count by the size you mostly use. If you have not packed yet, count shelves and cupboards instead: a full 3 ft shelf of books is roughly two small boxes.
Appliances, at 30 cu ft each. A full-size fridge measuring 36 × 33 × 70 in is 48 cu ft; a washer at 27 × 30 × 38 in is 18 cu ft. Thirty is the working average across the fridge, freezer, washer, dryer and range that a mover would crate separately. If you are only taking a washer and dryer, the total is closer to 36 cu ft than 60, and you can reflect that by entering one appliance instead of two.
The loading allowance. Nobody fills a box truck to 100% of its rated volume. Mattresses lean, tabletops cannot be stacked on, and you leave a gap at the door for the last-minute items and the tie-down straps. Ten to fifteen per cent is the realistic allowance for a self-loaded move; a professional crew that disassembles beds and builds a tight wall of cartons gets closer to the rating, and a rushed move with no packing plan needs more. The allowance applies to the volume only — the weight figure is calculated from the contents themselves, because the extra space is air.
Trips follow from ceiling division: you cannot make 0.4 of a journey, so any remainder rounds a whole trip up. Driving distance is not simply distance × trips either. With t journeys you drive t loaded legs and t − 1 empty return legs, which is (2t − 1) one-way distances in total.
Worked example: a two-bedroom flat moving 20 miles
Two bedrooms, a living room and a kitchen with furniture, 30 medium cartons, a washer and a fridge. You are loading it yourself, so allow 10%.
- Furniture. 2 + 2 = 4 furnished rooms × 150 cu ft = 600 cu ft. The flat is a rental with modest furniture, so 150 rather than 175.
- Boxes. 30 × 3.0 = 90 cu ft.
- Appliances. 2 × 30 = 60 cu ft.
- Contents volume. 600 + 90 + 60 = 750 cu ft.
- Add the allowance. 750 × 1.10 = 825 cu ft of truck space.
- Match a truck. 400 is too small, 760 is too small, 1,000 fits. Book the 20 ft truck, and you will have 175 cu ft spare — about a fifth of the box, which is your margin for the things you always forget.
- Weight check. 750 cu ft × 7 lb/cu ft = 5,250 lb. Well inside the payload of a 20 ft rental, so volume is the binding constraint here.
Now suppose you try to save money with the 10 ft truck at 400 cu ft. Journeys = ⌈825 ÷ 400⌉ = 3. Over a 20-mile move that is 3 loaded legs and 2 empty returns, so 5 × 20 = 100 miles of driving. At 8 mpg and $4.00 a gallon that is 12.5 gallons and $50.00 in fuel, against 20 miles and $10.00 for the single run in the bigger truck. Add three round trips of loading and unloading and the small truck has stopped being cheap.
Reading the result before you book
Aim for one journey with space to spare. The single most useful output here is the spare capacity figure. Zero spare space means a perfect pack with no margin, and no self-loaded move packs perfectly. If the spare figure comes out under about 10% of the truck's capacity, look at the next size up and price the two against each other, adding the extra day's hire you will need if the pack goes wrong.
Check the weight as well as the volume. Household goods average close to 7 lb per cubic foot, so a full 1,600 cu ft box is around 11,200 lb of goods. Most household loads run out of volume before they run out of payload, but a load that is mostly books, tools, weights or tiles inverts that. Weigh a sample rather than guess: fill one medium carton with books, put it on the bathroom scales, and divide by its 3.0 cu ft to get your own density for that part of the load. Any figure well above 7 means the payload plate, not the box volume, is your limit. Never exceed the payload printed on the truck; brakes and tyres are rated for it.
Watch the driving licence and the height. In the United States, consumer rental trucks are deliberately specified under the 26,001 lb gross weight rating at which 49 CFR Part 383 requires a commercial driver's licence, so a standard licence covers even the 26 ft box. Low bridges, drive-through canopies and car parks with height bars do not care about that: read the clearance height printed in the cab and check it against the route, not just the load.
Treat the recommendation as a floor. The calculator returns the smallest truck that holds the load. Where two sizes are close and the price difference is small, the larger box is easier to load because you can stand furniture up rather than playing tetris, and easier to strap because you have room for a proper wall between tiers.
Cubic feet and truck size by home size
| Home | Furnished rooms | Boxes | Appliances | Contents (cu ft) | With 12% allowance | Weight at 7 lb/cu ft | Truck |
|---|---|---|---|---|---|---|---|
| Studio | 2 | 20 | 1 | 440 | 493 | 3,080 lb | 15 ft |
| 1-bed apartment | 3 | 30 | 2 | 675 | 756 | 4,725 lb | 15 ft |
| 2-bed apartment | 4 | 40 | 3 | 910 | 1,019 | 6,370 lb | 26 ft |
| 3-bed house | 6 | 60 | 4 | 1,350 | 1,512 | 9,450 lb | 26 ft |
| 4-bed house | 8 | 80 | 5 | 1,790 | 2,005 | 12,530 lb | 26 ft × 2 trips |
The 2-bed row lands 19 cu ft over the 1,000 cu ft of a 20 ft truck — that is exactly the margin a tighter pack or ten fewer boxes recovers, and a good illustration of why you should test your own numbers rather than trust a home-size chart.
Where truck estimates go wrong
- Counting rooms instead of furnished rooms. A home office with a laptop on a shelf is not 175 cu ft of furniture. Count what actually gets carried out.
- Forgetting the garage, loft, shed and basement. These are not rooms in the allowance and they are frequently the largest single surprise on moving day. Add their contents as extra boxes and appliances.
- Ignoring the loading allowance. Booking to the exact contents volume guarantees a second journey, because a real load never packs to 100%.
- Assuming a small truck is cheaper. The daily rate is only one term. Add the extra mileage, the extra fuel and the extra hours before you compare.
- Sizing by weight alone. Duvets, sofas and garden furniture weigh little and fill a truck; books, tools and tiles do the opposite. Size by volume, then check the weight against the payload plate.
- Overlooking what cannot legally travel. Fuel, propane cylinders, paint, aerosols and other hazardous items are excluded from rental agreements and from professional shipments; they do not belong in the cube either.
- Not measuring the doorways. Volume gets the load onto the truck; it says nothing about whether the sofa turns the corner in the stairwell at the other end.
How this compares with a professional estimate
A licensed interstate mover does not sell you cubic feet — it charges by weight, established by weighing the loaded truck, with the cube sheet used only to build the estimate. That is why FMCSA's consumer guidance concentrates on written estimates, the difference between binding and non-binding, and your right to see the weight tickets. If you are hiring a carrier, expect the estimate to arrive in pounds and convert it back at the 7 lb per cubic foot rule if you want to sanity-check the truck they are sending.
For a self-move, the cube is the whole story, and the arithmetic here is the same one the estimator uses. Combine it with the money side: the moving cost calculator handles the rate, mileage charges, insurance and labour that sit on top of the vehicle, and the self storage unit size calculator uses the same contents volume to size a unit if your dates do not line up at both ends. When you are working from plans or a listing in metric, the cubic yards to cubic feet calculator and the square feet to square meters calculator keep the units straight, and the mpg to L/100km calculator converts a European van's economy figure into something you can put in the fuel field above. If the move involves getting to a roof or a loft hatch, size the ladder with the ladder length and angle calculator before the day rather than on it.
Key terms
- Cube sheet
- The mover's inventory list, with a cubic-foot allowance beside each item, used to build the volume of a shipment before it is weighed.
- Payload
- The maximum weight of cargo a truck may carry — gross vehicle weight rating minus the truck's own empty weight. It is printed on a plate in the cab or door frame.
- Loading allowance
- The proportion of the box you cannot fill because of awkward shapes, aisles and the tie-down gap. Applied to volume only.
- Binding estimate
- A written price from a carrier that does not change with the final weight, provided the inventory does not change. A non-binding estimate is re-priced from the actual weight.