The depreciable life of a trailer used in business is five years under the General Depreciation System in MACRS, with a six-year life under the Alternative Depreciation System. In practice, most buyers never spread the deduction that long: Section 179 and 100% bonus depreciation usually let you write off the full cost in the year the trailer is placed in service.
Why Trailers Are Five-Year Property
The IRS assigns trailers and trailer-mounted containers to Asset Class 00.27 in Revenue Procedure 87-56. That class carries a five-year GDS recovery period and a six-year ADS recovery period.1Internal Revenue Service. Rev. Proc. 87-56 – ACRS Depreciation Dry vans, flatbeds, reefers, and most other over-the-road hauling equipment fall here.
Classification turns on how you use the trailer in your business, not how it’s built. The same box trailer can land in different property classes depending on whether it’s hauling freight or sitting on blocks as a jobsite office.
How the Five Years Actually Play Out
Under GDS, five-year property is depreciated using the 200% declining balance method, which front-loads the deductions and automatically switches to straight-line partway through when that produces a larger write-off.2Internal Revenue Service. Publication 946 (2025), How To Depreciate Property
The half-year convention treats a trailer placed in service at any point during the year as if you started using it at the midpoint. You claim half a year of depreciation in year one and the remainder in a sixth tax return. If more than 40% of your total depreciable property for the year goes into service in the last quarter, the mid-quarter convention replaces the half-year convention and shrinks your year-one deduction further.
MACRS assumes zero salvage value. You depreciate the full cost basis without subtracting an expected resale price.
Writing Off the Trailer in Year One
The five-year schedule is often moot, because two provisions let you deduct most or all of the cost immediately.
Section 179
Section 179 lets you expense the full purchase price of qualifying business property in the year it’s placed in service, up to an annual cap. The base limit is $2,500,000, adjusted for inflation; for 2026 the limit is approximately $2,560,000, and the deduction phases out dollar-for-dollar once total equipment purchases exceed $4,000,000.3Office of the Law Revision Counsel. 26 USC 179 – Election to Expense Certain Depreciable Business Assets
The trailer must be used more than 50% for business. The deduction is capped at your taxable income from active trades or businesses, so it cannot create or deepen a net operating loss. Unused amounts carry forward.
Bonus Depreciation
The One, Big, Beautiful Bill Act, signed in 2025, restored permanent 100% bonus depreciation for qualified property acquired after January 19, 2025.4Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One, Big, Beautiful Bill A trailer placed in service in 2026 can be written off entirely in year one. Bonus has no dollar cap and can create or increase a net operating loss.
Used trailers qualify, but with conditions: the trailer cannot be one you previously used, it cannot come from a related party, and your basis cannot be determined by the seller’s basis.5Internal Revenue Service. Additional First Year Depreciation Deduction (Bonus) – FAQ An arm’s-length purchase from an unrelated seller is the typical qualifying case.
You can stack the two by applying Section 179 first and bonus to the remaining basis. With bonus back at 100%, most buyers simply take bonus on the full cost. Section 179 is more useful when you want to control the size of a net operating loss or carry unused deductions forward. Both deductions are reported on Form 4562, which must accompany your return whenever you claim depreciation on property placed in service during the year or elect Section 179.6Internal Revenue Service. Instructions for Form 4562
When the Life Is Not Five Years
A few situations push a trailer out of the standard five-year bucket.
Used Farm Equipment
New farm machinery and equipment placed in service after 2017 depreciates over five years under GDS. Used farm equipment keeps the older seven-year recovery period.7Internal Revenue Service. Publication 225 (2025), Farmer’s Tax Guide A new grain trailer runs five years; a secondhand one you buy at auction runs seven.
Industry-Specific Classes
Revenue Procedure 87-56 contains dozens of industry-specific asset classes, and a trailer whose primary function fits one of them follows that class instead of 00.27. A logging trailer used by a sawmill operator, for example, would typically track with logging equipment. Checking the tables before filing is worth the effort.
Office or Storage Trailers
Construction companies often park trailers on job sites for months or years as temporary offices, tool cribs, or storage. When a trailer is set on blocks, hooked to utilities, and used as a stationary structure, the IRS may treat it as something other than transportation equipment and assign a longer recovery period. The deciding factor is whether the trailer’s primary function during the tax year is transportation or serving as a building.
Mobile Homes as Rentals
A trailer or mobile home rented out as a dwelling is a different animal entirely. If 80% or more of a structure’s gross rental income comes from dwelling units, it is residential rental property with a 27.5-year recovery period.2Internal Revenue Service. Publication 946 (2025), How To Depreciate Property A mobile home rented as a tenant’s residence fits regardless of whether it still has wheels.
Mandatory ADS
The Alternative Depreciation System stretches the recovery period to six years and requires straight-line depreciation. It is mandatory when the trailer is used predominantly outside the United States, leased to a tax-exempt organization, financed with tax-exempt bond proceeds, used 50% or less for business as listed property, or when you elected out of uniform capitalization rules for farm property.6Internal Revenue Service. Instructions for Form 4562 You can also elect ADS voluntarily. Once elected for a property class in a given year, the election is irrevocable and applies to all property in that class placed in service that year.
Business Use and Listed Property
Trailers used for transportation can fall under the IRS’s listed property rules unless they qualify as nonpersonal use vehicles, meaning they are modified so personal use is inherently unlikely.2Internal Revenue Service. Publication 946 (2025), How To Depreciate Property A heavy-duty commercial flatbed probably qualifies for the exception. A small enclosed trailer you also use for personal hauling on weekends probably does not.
When a trailer is listed property, you have to document the date, business purpose, and mileage of each use. Without adequate records, you lose the right to claim depreciation or Section 179 at all.
The 50% business-use threshold matters beyond Section 179 eligibility. If business use drops to 50% or less in any year, you lose accelerated depreciation entirely, switch to straight-line over the longer ADS recovery period, and may have to recapture excess depreciation claimed in earlier years.6Internal Revenue Service. Instructions for Form 4562 Recapture gets added to income in the year usage drops. A simple mileage log kept from day one prevents the problem.
Recapture When You Sell
Fast deductions have a tail. Under Section 1245, gain on the sale of depreciable personal property is taxed as ordinary income to the extent of the depreciation previously claimed.8Office of the Law Revision Counsel. 26 US Code 1245 – Gain From Dispositions of Certain Depreciable Property This covers trailers depreciated under regular MACRS as well as trailers fully expensed through Section 179 or bonus depreciation.
Say you bought a trailer for $50,000, expensed the full amount in year one, and sold it three years later for $20,000. The entire $20,000 is ordinary income rather than capital gain, because it falls within depreciation already deducted. Recapture cannot exceed the total depreciation you took; any gain above the original purchase price would be capital gain. Recapture is subject to ordinary income tax rates but not to self-employment tax.
Any sale price above zero on a fully depreciated trailer triggers recapture. Owners who deducted the full cost under Section 179 or bonus and then sell years later are often caught by the resulting bill. Planning for it at the time you take the deduction is the fix.
State Conformity
Federal and state depreciation rules do not always match. Many states conform to the federal system, but a significant number decouple from bonus depreciation. A decoupling state will not allow the same first-year write-off on your state return even though you claimed it federally, which means you depreciate the trailer over the full five-year schedule on the state side while deducting 100% in year one federally. Those timing differences need to be tracked. Check your state’s current position, since conformity decisions can shift from year to year.