1031 Exchange Deadline Calculator
Enter your sale closing date. See your exact 45-day identification deadline and 180-day exchange completion deadline — and whether you need to file a tax extension to protect the full 180-day window.
How the 1031 exchange clock works
The moment you close on the sale of your relinquished property, two clocks start simultaneously — and neither stops until the exchange is complete or fails.
- 45 calendar days to identify replacement property candidates in writing to your qualified intermediary
- 180 calendar days (or your tax return due date, whichever is earlier) to close on the replacement property
Both deadlines are hard. There are no extensions, no grace periods, and no pauses for financing delays, market disruption, or title complications — unless a federally declared disaster covers your exchange period, which is rare and requires a specific IRS notice.
The 45-day identification period cannot be extended under any circumstance short of a presidentially declared disaster. If you miss the identification deadline, the exchange fails and the full gain becomes taxable in the year of sale. The IRS holds this rule strictly.
The 180-day clock does have one built-in constraint: it cannot extend past the due date of your tax return for the year of the sale. For most individuals, that means April 15 — unless you file an extension.
The extension trap: late-year closings
This is the most common and most costly deadline mistake for investors who close in the fourth quarter.
Consider an individual investor who closes a sale on November 20. The 180-day window runs to May 19 of the following year. That's fine on its face — but the investor's income tax return for the year of the sale is due April 15. Per IRC §1031(a)(3)(B), the exchange must be complete by the earlier of 180 days or the return due date.
Without a filing extension, that April 15 return deadline becomes the effective exchange deadline — cutting the window from 180 days to roughly 145. A investor who doesn't realize this can find themselves in contract on a replacement property that's due to close in May, only to discover the exchange clock expired in April.
- Individuals file Form 4868 by April 15 — no tax payment required, no reason needed
- S-corps and partnerships file Form 7004 by March 15
- The extension pushes the return due date to October 15 (individual) or September 15 (S-corp/partnership), which is almost always after the 180-day window — preserving the full exchange period
The extension does not give you more time than 180 days. If your 180-day deadline falls before the extended return date, the 180-day rule still governs. The extension only matters when 180 days would otherwise push past the unextended return date.
Identification deadline mechanics
The 45-day window ends at midnight on the 45th calendar day after closing. Identification must be in writing, signed, and delivered to your qualified intermediary (or other party on the other side of the exchange) before that deadline.
Three identification rules apply — you must satisfy at least one:
- Three-Property Rule: Identify up to three replacement properties of any value. Most investors use this rule.
- 200% Rule: Identify any number of properties as long as their combined fair market value does not exceed 200% of the relinquished property value.
- 95% Rule: Identify any number of properties, but you must close on at least 95% of the total identified value by the 180-day deadline.
For a deeper breakdown of identification rules with worked examples, see our 45-Day Identification Rules guide.
Common deadline mistakes
- Counting business days instead of calendar days. The 45 and 180 periods are strictly calendar days. Weekends and holidays count except that, per IRC §7503, a deadline falling on a Saturday, Sunday, or legal holiday moves to the next business day.
- Missing the extension filing for fourth-quarter closings. A November or December close triggers the extension trap described above. The extension form must be filed by the unextended return due date — you cannot file it retroactively after the due date passes.
- Confusing the reverse exchange clock. In a reverse 1031 exchange, the 180-day clock starts from the date the Exchange Accommodation Titleholder (EAT) acquires the replacement property — not the date you close on the sale of your relinquished property. The two clocks in a reverse exchange can be more complex; see our Reverse Exchange guide.
- Assuming the QI can pause the clock. Your qualified intermediary has no authority to extend the statutory deadlines. A QI failure — fraud, bankruptcy, or administrative breakdown — does not pause or restart the clock. This is another reason why QI selection matters. See our QI Selection guide.
- Not building in buffer time before the 45-day deadline. Identification letters typically need to be received, not just sent, before midnight on day 45. Use certified mail or written confirmation of receipt. Sending an email on day 44 at 11 PM and hoping it's received in time is a risk not worth taking.
Sources
- IRC §1031 — Property Used in a Trade or Business and Involuntary Conversions (Cornell LII) — §1031(a)(3) sets the 45-day and 180-day deadlines.
- Treas. Reg. §1.1031(k)-1 — Treatment of deferred exchanges (eCFR) — detailed mechanics for identification, receipt, and QI rules.
- IRC §7503 — Time for Performance of Acts Where Last Day Falls on Saturday, Sunday, or Legal Holiday (Cornell LII) — weekend and holiday extension rule.
- IRS Publication 544 — Sales and Other Dispositions of Assets — IRS guidance on reporting like-kind exchanges; values verified as of June 2026.
Deadline calculations are based on calendar-day counting per IRC §1031(a)(3) and Treas. Reg. §1.1031(k)-1. Weekend adjustments reflect IRC §7503. This calculator assumes a calendar-year taxpayer. Fiscal-year entities, taxpayers in presidentially declared disaster zones, and other unusual circumstances may have different deadlines. Verify all deadlines with your qualified intermediary and tax advisor before relying on them for transaction decisions. Values and rules current as of June 2026.
Get matched with a specialist financial advisor
A 1031 exchange has moving parts beyond the deadlines: debt replacement, boot risk, DST selection, retirement income modeling, and estate planning. A fee-only advisor who specializes in real estate liquidity events can coordinate with your QI, CPA, and attorney before the 45-day clock forces a decision.