The 8×20 is the smallest mobile office trailer most yards stock — 160 square feet, comfortable for two people, and the only common size narrow enough to move without an oversize permit. Rentals run $200 to $400 per month; a used unit sells for $3,500 to $9,000.
8×20 Mobile Office Trailer Specifications
| Nominal size | 8×20 |
|---|---|
| Floor area | 160 sq ft |
| Exterior width | 8 ft — under the legal load width in most states |
| Working occupancy | 1 to 3 people |
| Typical layout | Open plan, single room |
| Restroom | Rare at this size |
| Monthly rental | $200 – $400 |
| Buy new | $8,000 – $16,000 |
| Buy used | $3,500 – $9,000 |
A note on the name. Unlike the larger sizes, an 8×20 is usually sold by its box dimension — the 20 feet is the floor, and any hitch is additional. On a 12×60 the opposite is true: the 60 feet is the towing length and the box is 56. Ask which convention a supplier is quoting before you compare two units on square footage.
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How Much Does An 8′ x 20′ Mobile Office Trailer Cost?
Renting
$200 to $400 per month on a typical lease, and the low end of that range is realistic only on a longer term. Expect the monthly rate to fall as the term lengthens — twelve months prices very differently from three.
The monthly figure is not the cost of having one on site. Delivery and pickup, blocking and leveling, steps or a ramp, and skirting are all separate, and on a short rental they routinely exceed a year of rent. Ask for the full first-year number rather than the monthly rate.
Buying
$8,000 to $16,000 new and $3,500 to $9,000 used. The 8×20 has the widest new-to-used gap of any size, because it is the unit most often bought outright by small contractors and resold privately rather than through a national lessor’s fleet-disposal channel.
Most 8×20 mobile office trailers for sale come from one of four places: national lessors clearing older fleet stock, regional dealers, contractor auctions and liquidations, and private owners selling at the end of a job. The private-sale channel is where the cheapest units are and where the least inspection has been done — on a unit this small, check the floor around the door and under any window for soft spots before anything else, because water damage is what kills them.
Break-even is about 21 months. At a mid-range $300 per month against a mid-range $6,250 used purchase, renting costs more than buying somewhere around the twenty-first month — before counting the resale value you keep at the end. If the trailer will be on site longer than roughly two years, buying is usually the cheaper answer. Shorter than that, renting is, because the delivery and setup costs land either way.
What Actually Fits In 160 Square Feet
Suppliers list the 8×20 at up to three occupants. That is achievable and not comfortable. For reference, an open-plan workstation is normally planned at 50 to 75 square feet per person and a private office at 100 to 150.
| People | Square Feet Each | In Practice |
|---|---|---|
| 1 | 160 | Generous. Desk, plan table, files and a visitor chair |
| 2 | 80 | Comfortable. Two desks facing, room for a plan table |
| 3 | 53 | Tight. Works for a crew that is mostly out on site |
The practical constraint is usually not headcount but what else has to live in the trailer. A plan table, a printer, a job-site safety station and a coffee setup consume floor faster than a third desk does. If the trailer is also the meeting room where subs and inspectors get walked through drawings, plan for two people and the table.
Ground Level Or Towable?
The 8×20 is available both ways, and it is the main specification decision at this size.
Ground Level
Container-style or skid-mounted, sitting at grade. No steps, no ramp, easier ADA compliance, lower profile in a neighborhood where a raised trailer draws complaints. Set with a forklift or roll-off truck.
Towable
On a chassis with axles and a hitch. Faster to move, cheaper to relocate repeatedly, and the standard choice where the trailer follows the crew from job to job. Needs steps and a landing, and a ramp if the public will enter.
If the unit will sit for the length of one project and then move, towable is usually right. If it will stay put for years or the public will use it, ground level saves the ramp and the ongoing complaints about the stairs.
Delivery And Placement
The 8×20’s real advantage over every larger size is its width. In most states the legal load width is 8 feet 6 inches, so an 8-foot-wide unit travels as a standard load — no oversize permit, no pilot car, no route survey. A 10-foot or 12-foot-wide trailer needs all three, and that difference shows up in the delivery charge on every move.
What still needs planning:
- A firm, reasonably level pad. Blocking absorbs a few inches; it does not fix a slope.
- Truck access. A tractor and trailer needs room to swing and back. Tight urban lots are where 8×20 deliveries actually fail.
- Power. Typically a single 100-amp service, though a small unit with modest load may run on less. Confirm the panel spec against what the site can supply.
- Steps and a landing on a towable, and a ramp if anyone other than staff will enter.
When To Size Up
The 8×20 is the right unit for a small crew, a gate office, a security post or a satellite office on a larger site. Size up when any of these is true:
- More than three people work in it daily — the 8×36 or 10×40 is the usual next step.
- You need a restroom. Restroom-equipped 8x20s exist but are rarely stocked; availability starts in earnest above 10×40.
- You need a separate private office for confidential conversations or a lockable document room.
- It is the project meeting room. Six people around drawings needs a double wide, not a single.
Our office trailer rental guide compares every size on rate, square footage and occupancy, and the for-sale guide covers new and used pricing across the range.
8×20 Office Trailer FAQ
How much does an 8×20 mobile office trailer cost?
New units run $8,000 to $16,000 and used units $3,500 to $9,000. Renting costs $200 to $400 per month, with the lower end available only on longer lease terms. Delivery, set, steps and skirting are charged separately in all three cases.
How big is an 8×20 office trailer?
160 square feet — 8 feet wide by 20 feet long. At this size the 20 feet normally describes the box itself, with any hitch additional, which is the opposite of the convention used on larger units like the 12×60 where the nominal length includes the hitch.
How many people fit in an 8×20 office trailer?
Two comfortably, three if the crew is mostly out on site. That works out to 80 square feet per person at two and 53 at three, against a normal planning figure of 50 to 75 square feet for an open-plan workstation. What usually decides it is not headcount but whether a plan table, printer and meeting space also have to fit.
Is it cheaper to rent or buy an 8×20 office trailer?
Break-even lands around 21 months, comparing a mid-range $300 monthly rental against a mid-range $6,250 used purchase — and that is before the resale value you keep. Longer than about two years on site, buying usually wins. Shorter than that, renting does, because delivery and setup are charged either way.
Does an 8×20 office trailer need an oversize permit to move?
Usually not. The legal load width in most states is 8 feet 6 inches, so an 8-foot-wide unit moves as a standard load with no oversize permit, pilot car or route survey. Wider units at 10 and 12 feet need all three, which is why delivery on an 8×20 costs meaningfully less per move.
Can you get an 8×20 office trailer with a bathroom?
They exist but are rarely stocked at this size, and availability only becomes common above 10×40. On a construction site the usual answer is to pair a standard 8×20 with portable toilets, which is cheaper and satisfies OSHA sanitation requirements independently of the trailer.
What power does an 8×20 office trailer need?
Typically a single 100-amp service, though a lightly loaded unit may run on less. Confirm the panel specification on the specific trailer against what the site can supply, because the connection is usually the tenant’s responsibility rather than the lessor’s.
Compare 8×20 Office Trailer For Sale Prices
Tell us whether you want an 8×20 mobile office trailer for sale or for rent and where it is going, and we will connect you with suppliers who stock this size. Rates and delivery charges vary widely by yard, and comparing several quotes is the only way to see the spread. There is no cost and no obligation.
Related Guides
- Office Trailer Rental — monthly rates, sizes and lease terms across the range
- Office Trailers For Sale — new and used prices, where to buy, what to inspect
- Portable Restrooms — the usual pairing where the trailer has no bathroom