The short answer
Yes, the business-use portion can be exchanged, but for an office inside your living space the home-sale exclusion already covers most of it. Under Reg. section 1.121-1(e), no allocation is required when the office and the home are in the same dwelling unit, so the whole gain counts toward the $250,000 or $500,000 exclusion except the depreciation claimed after May 6, 1997. A section 1031 exchange of the office share earns its cost only when that depreciation is large or the gain is above the cap, and it requires buying separate business or investment real estate worth at least the office's share of the price.
At a glance
| Office inside the house | No allocation; the exclusion reaches the office share |
|---|---|
| Always taxable without an exchange | Depreciation allowed or allowable after May 6, 1997 |
| Separate studio or outbuilding | Allocated; its gain is outside the exclusion unless you lived in it |
| Exchange order | Exclusion first, then section 1031 on what remains |
| Replacement needed | Business or investment real estate at least equal to the office share |
| Cash received | Taxed only to the extent it exceeds the excluded gain on the office share |
| Reporting | Two worksheet Forms 8824 combined on the one you file |
An office within the living space shares the home's exclusion, all except its depreciation
Reg. section 1.121-1(e)(1) says no allocation is required if the residential and non-residential portions are within the same dwelling unit. Its Example 5 is an attorney with a law office in the house who excludes all of a $13,000 gain except the $2,000 of depreciation.
That $2,000 is the part section 121(d)(6) denies: gain equal to depreciation adjustments after May 6, 1997. Publication 587 adds that the figure is depreciation allowed or allowable, even if you never claimed it, while the allowable amount is deemed to be zero for any year you used the simplified method. Meanwhile Publication 523 says the business part inside your home is not reported separately on Form 4797.
So for most owners the question is not whether the office can be exchanged, but whether a few thousand dollars of depreciation is worth an exchange.
The IRS example exchanges the office share and defers exactly the depreciation
In Example 3 of Rev. Proc. 2005-14, a taxpayer uses one-third of a single-dwelling-unit house as a business office and claims $30,000 of depreciation. The house is exchanged for a new residence and a separate office property worth $120,000, equal to the office share of the old house.
The residential share's $100,000 gain is excluded. Of the office share's $80,000 gain, $50,000 is also excluded because the office sat inside the dwelling unit, and the $30,000 of depreciation is deferred under section 1031.
Example 6 shows when it matters more. With a $750,000 sale, the residential share alone uses the full $250,000 exclusion, leaving $110,000 taxable, and the office share's entire $210,000 gain is deferred by the exchange.
Worked example: is deferring $30,000 of depreciation worth buying $120,000 of real estate?
Hypothetical, round figures. Using the Example 3 numbers, the $30,000 of depreciation would be unrecaptured section 1250 gain taxed at up to 25% under Topic 409, or at most $7,500 of federal tax.
To defer it, you must buy separate business or investment real estate worth at least the $120,000 office share, through a qualified intermediary, within the 45- and 180-day deadlines of Reg. section 1.1031(k)-1. The replacement then carries a low basis and any later sale brings the deferred gain back.
If you were going to buy a small rental or business property anyway, routing the office share through an exchange costs little beyond the intermediary's fee. If not, paying the tax is usually simpler, and it leaves the proceeds free for your next home. The calculation flips when the total gain is well above the exclusion, because then the office share is carrying taxable appreciation as well as depreciation. Run your own numbers with your CPA.
A detached studio or workshop is a different case and behaves like a rental unit
Space separate from the dwelling unit is allocated. Publication 587 says you cannot exclude gain on a separate part used for business unless you owned and lived in that part for two of the five years before the sale, and the sale of that part goes on Form 4797.
For a separate studio the exchange is the main relief, as with the guesthouse in Example 2 of Rev. Proc. 2005-14. The mechanics match those for a rented ADU and for one side of a duplex.
Allocate price and basis by the method you used for depreciation, with square footage accepted under Reg. section 1.121-1(e)(3).
What to do before you list, and where a fractional interest fits
Pull your depreciation history for the office from prior returns. If it is small and your total gain is under the cap, the exchange is likely not worth setting up.
If you exchange, the Form 8824 instructions have you prepare one worksheet for the home part and one for the business part and combine them; cash you receive counts as boot only beyond the excluded gain on the office share, as Example 4 of Rev. Proc. 2005-14 shows.
An office share is often an odd amount. A Delaware Statutory Trust interest, accepted as real property by Rev. Rul. 2004-86, can be sized to it; see how DST interests qualify and weigh the trust's fees and illiquidity first.
Related questions
Do I have to report the office part on Form 4797?
Not when the office is inside your home. Publication 523 says you do not report the business part separately, but you still recognize gain equal to post-May 6, 1997 depreciation.
I used the simplified home-office deduction. Is there depreciation to worry about?
Publication 587 says the depreciation allowable for the office is deemed to be zero for any year you used the simplified method. Years in which you deducted actual expenses still count, so check your method year by year.
Can the office share buy part of my next home?
No. The replacement for the office share has to be business or investment property; a new residence is personal-use property.
Does my W-2 remote-work office count as business use?
The IRS examples involve a taxpayer using the office in their own trade or business. Whether an employee's home workspace is held for productive use in a trade or business is a fact question to settle with your CPA.
What if my gain is far above the exclusion?
Then the office share may be worth exchanging, because, as in Example 6 of Rev. Proc. 2005-14, the residential share can absorb the whole exclusion and leave the office share's gain fully taxable unless exchanged.
Sources
Checked against these publications on September 30, 2026. Rules and figures change; confirm the current version with your CPA or attorney before you act. This page is general information, not tax or legal advice.
- Treas. Reg. Section 1.121-1, property used in part as a principal residence
- 26 U.S.C. Section 1031
- 26 U.S.C. Section 121, exclusion of gain from sale of principal residence
- IRS Publication 587, Business Use of Your Home
- IRS Publication 523, Selling Your Home
- IRS, Rev. Proc. 2005-14, Internal Revenue Bulletin 2005-7
- IRS Topic 409, capital gains and losses
- Treas. Reg. Section 1.1031(k)-1, deferred exchanges
- IRS, Instructions for Form 8824 (2025)
- IRS, Internal Revenue Bulletin 2004-33 (Rev. Proc. 2004-51 and Rev. Rul. 2004-86)