Decision guide

The 1031 Exchange, Explained: Rules, Timelines, and the 2026 Tax Picture

A 1031 exchange defers — not erases — capital gains tax on investment real estate. The 45-day identification rule, the 180-day closing window, how boot and depreciation recapture are taxed, and why pairing an exchange with cost segregation and 100% bonus depreciation is the 2026 power move.

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Published: 2026-10-23

Updated: 2026-10-23

Quick Answer

The 1031 Exchange, Explained: Rules, Timelines, and the 2026 Tax Picture is worth reviewing before you trust a calculator result because the assumptions behind the model usually matter as much as the formula.

Key Takeaways

Confirm the property qualifies: real property held for investment or business use — not a personal residence, and U.S. property can't exchange into foreign property
Engage a qualified intermediary before closing — proceeds must go to the QI, never through your account
Mark both deadlines on a calendar: 45 days to identify, 180 days to close, calendar days, no weekend extensions
Identify replacements using the 3-property rule (or the 200% rule) within the 45-day window
Model boot: cash back, prorations, and any drop in mortgage balance all create taxable boot

What a 1031 exchange actually does

Section 1031 of the Internal Revenue Code lets an investor sell real property held for investment or business use and buy "like-kind" replacement property while deferring the capital gains tax — not eliminating it. The tax is postponed, not forgiven: your old property's adjusted basis carries over to the replacement, so the gain is still embedded in the property and comes due when you eventually sell for cash. To defer all of the gain, three things must hold: the replacement must be equal or greater in value, all of the equity must be reinvested, and a qualified intermediary must hold the sale proceeds — touching the cash yourself kills the exchange. There is no limit on successive exchanges, which is why investors talk about "swap till you drop": keep exchanging and the deferred gain keeps rolling, and heirs receive a stepped-up basis at death that can wipe it out entirely. That is also why the estate-tax exemption matters here — the 2026 law made it permanent at about $15 million per person (about $30 million for a couple), so most investor portfolios can now pass free of federal estate tax with deferred gains erased. This guide is educational only and is not tax or legal advice; a real exchange needs a qualified intermediary and usually a CPA or tax attorney.

What the 2026 tax law changed — and what it didn't

The One Big Beautiful Bill Act (P.L. 119-21, signed July 4, 2025) left Section 1031 completely untouched. CPA and tax sources are in consensus: like-kind exchanges of real property "remain intact" and "came through the OBBBA completely untouched," and earlier proposals that would have capped deferrals at $500,000 were not included in the final law. So the exchange rules investors have used for decades apply in full force in 2026. What did change is bonus depreciation: the same law permanently restored 100% bonus depreciation for qualifying property acquired after January 19, 2025 — which pairs powerfully with exchanges, covered in the combo section below. One caution: a few outlier sources have mischaracterized pre-existing rules (the related-party 2-year rule, the foreign-property exclusion) as new OBBBA limits on exchanges. The consensus across CPA firms is that Section 1031 was untouched — do not plan around phantom restrictions.

The two deadlines: 45 days to identify, 180 days to close

The clock starts the day your relinquished property sells. You get 45 calendar days to identify replacement properties in writing, and 180 calendar days total to close on them — the two windows run concurrently, not back to back. These are calendar days: weekends and holidays do not extend them (the IRS does grant relief in federally declared disaster areas, but that is exceptional, not automatic). Worked example: sell on March 15, 2026. The day after closing counts as day 1, so you have 16 days left in March (March 16–31) plus 29 days in April — day 45 is April 29, 2026. For the 180-day window: 16 (rest of March) + 30 (April) + 31 (May) + 30 (June) + 31 (July) + 31 (August) = 169, so day 180 lands on September 11, 2026. Miss the 45-day identification deadline and the exchange fails, full stop — the full gain becomes taxable. Put both dates on a calendar the day the sale closes.

The identification rules: three ways to name your replacements

Within those 45 days, you identify replacement properties in a signed writing delivered to the qualified intermediary (or another eligible party) — a verbal plan does not count. The 3-property rule is the simplest and most common: identify up to three properties regardless of their value. The 200% rule: identify any number of properties as long as their combined fair market value does not exceed 200% of the relinquished property's sale price — useful when you want a menu of options. The 95% exception: if you exceed both limits, you can still qualify by actually acquiring at least 95% of the total value of everything you identified — a narrow escape hatch, not a planning strategy. Most straightforward exchanges live comfortably inside the 3-property rule, and the identification is worth doing in the first week, not the sixth: a property that falls through on day 40 leaves you no time to substitute.

Equal-or-greater value and the tax on boot: a $600,000 worked example

To defer all gain, the replacement property must be equal or greater in value, and you must reinvest all of your equity. Anything you keep — cash, or debt relief if the replacement carries a smaller mortgage — is "boot," and boot is taxable. Recognized gain equals the lesser of the boot or the total realized gain; the rest stays deferred. Worked example: you bought for $400,000 ($100,000 land, $300,000 building) and took $150,000 of depreciation, so your adjusted basis is $250,000. You sell for $600,000: realized gain is $350,000, made up of $150,000 of unrecaptured Section 1250 depreciation and $200,000 of capital gain. Exchange into a $600,000 replacement with no boot: $0 recognized now, $350,000 deferred, and the replacement's basis is $250,000 — your old basis carries over. Now take $60,000 of cash back instead ($540,000 property + $60,000 cash): you recognize $60,000 of gain — and recapture is recognized first, so that $60,000 is taxed as unrecaptured Section 1250 gain at up to 25%. The remaining $290,000 stays deferred, and the replacement basis works out to $250,000 − $60,000 + $60,000 = $250,000 (check: $540,000 − $250,000 = $290,000 of built-in gain still deferred). Debt counts too: swapping a $300,000 mortgage for a $260,000 one is $40,000 of boot unless you offset it with $40,000 of fresh cash at closing. Run the boot side in the 1031 exchange calculator before closing, including the debt.

Depreciation recapture doesn't disappear — it moves with you

An exchange defers gain; it does not forgive depreciation recapture. In a fully deferred exchange, the recapture character carries into the replacement property's basis — the unrecaptured Section 1250 amount (taxed up to 25% on a taxable sale) and any Section 1245 amounts ride along and will be taxed when the replacement is eventually sold for cash. This is the thread connecting this guide to the cost segregation calculator and the depreciation calculator: a cost-segregation study that accelerates $100,000 of a building into 5/7/15-year property creates bigger first-year deductions, but it also creates a larger recapture balance that an exchange carries forward rather than erases. And when boot does trigger recognized gain, recapture is taxed first — the worst-taxed dollars come out of hiding first. Deferred, not tax-free, and never assumed: state taxes follow their own conformity rules, so model your state separately rather than assuming the federal answer.

The 2026 power combo: defer on the way in, deduct on the way out

Here is the fresh angle most older guides miss. The 2026 law permanently restored 100% bonus depreciation for qualifying property acquired after January 19, 2025. An investor can sell via a 1031 exchange — deferring all of the gain — and then run a cost segregation study on the replacement property, writing off 100% of the 5/7/15-year components in year one. Illustrative: a $600,000 replacement with 20% land value leaves $480,000 of depreciable basis. Straight-line depreciation on the full $480,000 over 27.5 years is about $17,455 in year one. If a cost-seg study reclassifies $100,000 of that into 5/7/15-year property, the 100% bonus turns that $100,000 into a first-year deduction — nearly six times the straight-line amount, layered on top of the deferred gain from the exchange. Deferral on the way in, a first-year write-off on the way out. Model the combination with the cost segregation calculator and the depreciation calculator before assuming it fits your property — bonus only applies to qualifying components, and the study has to support the reclassification.

Reverse exchanges, DSTs, and related parties

Three advanced patterns, briefly. A reverse exchange — buying the replacement before selling the old property — uses the safe harbor of Revenue Procedure 2000-37: an exchange accommodation titleholder "parks" one of the properties for up to 180 days while you complete the other leg. Delaware Statutory Trust interests are treated as like-kind replacement property under Revenue Ruling 2004-86, which is how many exchangers access institutional-grade property without direct management — and a DSCR calculator is the natural way to underwrite the trust property's financing the way you would any rental. Related-party exchanges face a 2-year holding rule under Section 1031(f): both parties must hold their properties for at least two years after the exchange, or the deferral unwinds. All three are standard practice — and all three are where investors most often need a qualified intermediary and a CPA involved early, not after the contract is signed.

How exchanges actually fail

The failure modes are almost always procedural, not conceptual. Missing the 45-day identification deadline is fatal — there is no extension and no reasonable-cause relief in the ordinary case. Touching the sale proceeds, even briefly, is constructive receipt: the money must go from the closing table to the qualified intermediary, never through your account. The boot surprise is the most common partial failure: a smaller replacement mortgage, prorations, or cash back at closing creates taxable boot the investor didn't model — run the full picture in the 1031 exchange calculator before closing, including the debt side. A failed exchange isn't the end of the world mechanically: the intermediary returns the funds and the gain is recognized in the year you receive them. But it is the end of the deferral you paid the intermediary to protect, so the cheap insurance is a calendar, a qualified intermediary engaged before closing, and a CPA who has seen the whole structure.

Sources and fine print

Rule sources: IRC Section 1031; Revenue Procedure 2000-37 (reverse exchanges); Revenue Ruling 2004-86 (DSTs); Revenue Procedure 2008-16 (vacation-home safe harbor). OBBBA treatment: CLA ("Section 1031 like-kind exchanges... remain intact"); Schaaf CPA ("came through the OBBBA completely untouched," $500,000 cap proposals dropped, ~$15M-per-person estate exemption made permanent); HCVT (1031 plus FF&E planning); 1031 DealHub (45/180-day mechanics, qualified intermediary, cost-seg pairing). This guide is educational only and is not tax or legal advice. A valid exchange requires a qualified intermediary holding the proceeds and, in most cases, a CPA or tax attorney structuring it; state tax treatment of exchanges varies, and fees, deadlines, and property eligibility should be confirmed with your own advisors before you commit.

Checklist Before You Decide

Confirm the property qualifies: real property held for investment or business use — not a personal residence, and U.S. property can't exchange into foreign property
Engage a qualified intermediary before closing — proceeds must go to the QI, never through your account
Mark both deadlines on a calendar: 45 days to identify, 180 days to close, calendar days, no weekend extensions
Identify replacements using the 3-property rule (or the 200% rule) within the 45-day window
Model boot: cash back, prorations, and any drop in mortgage balance all create taxable boot
Track depreciation recapture: it's deferred into the replacement property, not erased — and it's taxed first if boot is recognized
Confirm the exchange structure and state tax treatment with a CPA or tax attorney before committing

FAQ

Did the new 2026 tax law change 1031 exchanges?

No — the One Big Beautiful Bill (signed July 4, 2025) left Section 1031 completely untouched, and earlier proposals to cap deferrals at $500,000 were dropped. The same law permanently restored 100% bonus depreciation, which pairs powerfully with exchanges on the replacement property.

How long do I have to complete a 1031 exchange?

45 calendar days from selling to identify replacement properties, 180 days total to close — the clock starts the day the old property sells, and weekends and holidays don't extend it. Missing the 45-day identification deadline fails the exchange outright.

Can I touch the sale money during a 1031 exchange?

No. A qualified intermediary must hold the proceeds; if you receive them, even briefly, the exchange fails and the gain is taxable. The money goes from the closing table to the QI, never through your account.

Does a 1031 exchange erase depreciation recapture?

No — it defers it. The recapture character carries into the replacement property's basis. But any "boot" (like cash back) triggers recognized gain, and recapture is taxed first, at up to 25%.

Can I exchange into a property worth less than the one I sold?

Yes, but the shortfall is boot — you'll owe tax on the difference or the full gain, whichever is smaller. A smaller replacement mortgage counts as boot too, unless you offset it with fresh cash at closing.

What is the 3-property rule?

The simplest identification path: within the 45-day window you may identify up to three replacement properties regardless of their value. If you need more, the 200% rule (any number, combined value at most 200% of the relinquished property) or the 95% exception apply.

Can I use a 1031 exchange for a vacation home?

It depends on use. The IRS safe harbor (Revenue Procedure 2008-16) covers dwelling units rented at least 14 days a year at fair rent with personal use limited to 14 days or 10% of rental days. A pure personal-use second home does not qualify.

What happens if I miss the 45-day identification deadline?

The exchange fails — the full gain becomes taxable. There is no ordinary extension; only IRS disaster-area relief can move the deadline, and that is exceptional, not automatic.