1031 Exchange Deadlines: The 45-Day and 180-Day Rules Explained (2026)

Most failed 1031 exchanges do not fail because the investor picked a bad property. They fail because someone missed a date by a day or two and assumed there would be wiggle room. There is none.

A like-kind exchange under Section 1031 runs on two deadlines that the IRS does not negotiate. You have 45 days to identify your replacement property in writing, and 180 days to close on it. Miss either one and the whole exchange collapses. The deferred gain becomes recognized gain, and the tax you were trying to push forward is due for the year you sold.

The good news is that both deadlines are simple once you see how they fit together. The trap is in the parts most people skip: when the clock actually starts, the tax-return rule that can shorten the 180 days, and the fact that weekends and holidays do not pause anything.

When the clock starts

Both periods begin on the same day. That day is the date you transfer the relinquished property, which in practice is the day it closes and the deed records. Not the day you list it, not the day you accept an offer, not the day the buyer wires earnest money. The closing date.

You can confirm the two dates instantly by entering your relinquished closing date in the 1031 exchange calculator. Everything below is just the logic behind those two outputs.

The 45-day identification deadline

You have 45 calendar days from the closing of your relinquished property to identify your replacement property in writing. The identification has to be signed by you and delivered to your qualified intermediary, or to another person involved in the exchange who is not a disqualified person, before midnight on day 45.

Three things trip people up here.

The identification must be in writing and specific. A street address or a clear legal description works. “A retail property somewhere in Austin” does not.

You can identify more than one property, but there are limits on how many and on their combined value. Those limits are the 3-property rule, the 200% rule, and the 95% exception, and they have their own identification rules guide. For the deadline itself, the only thing that matters is that the written list is delivered by day 45.

Once day 45 passes, the list is locked. You can close on a property you identified. You cannot swap in something new that you found on day 50, no matter how much better it is.

The 180-day closing deadline

You then have 180 calendar days from the same closing date to actually receive the replacement property. The 180 days includes the 45-day identification window. It is not 45 plus 180. It is 180 total, with the first 45 reserved for identifying.

So the practical sequence is: close on the sale, spend up to 45 days locking in your written identification, then spend the remaining time closing on something from that list, all before day 180.

The tax-return rule that can cut your time short

This is the part that surprises people, and it is the reason the calculator shows a note next to the 180-day date.

Your replacement period ends on the earlier of two dates: 180 days after the sale, or the due date of your federal income tax return (including extensions) for the tax year in which you sold. If you sell late in the year, your return due date can arrive before your 180 days are up.

Say you close on a sale in late November. Your 180 days would run into the following May. But your tax return for the year of sale is due around April 15. If you file that return before completing the exchange, your replacement period ends on the filing date, which is well short of 180 days. The fix is straightforward: file an extension so you keep the full 180 days. People who do not know this rule sometimes file early out of habit and shorten their own window by accident.

Weekends and holidays do not pause the clock

The 45-day and 180-day periods are counted in calendar days. They are not extended because day 45 lands on a Saturday or a federal holiday, which is different from how a lot of other tax deadlines work. If your day 180 is a Sunday, it is still your day 180.

The narrow exception is a federally declared disaster. The IRS can grant extensions when your property or your principal place of business sits in a declared disaster area, under the relief procedures in Rev. Proc. 2018-58. That is the only common way these dates move, and it is out of your control. Plan as if there is no extension.

A worked timeline

Here is a real example using the calculator so the numbers are exact.

You sell a rental for $800,000 and it closes on June 20, 2026. Your replacement target is a $950,000 property. The two deadlines fall on:

45-day identification deadline: August 4, 2026
180-day closing deadline: December 17, 2026

That is your whole timeline. Identify in writing by August 4. Close by December 17. Because the sale happened in June, the tax-return rule does not bite here, since your 2026 return is not due until 2027. If that same sale had closed in November, you would want to extend your return to protect the back end of the 180 days.

What to do with this

Put both dates on a calendar the day your sale closes, then work backward. Line up your qualified intermediary before closing, not after, because you cannot touch the proceeds at any point. Start shortlisting replacement properties during escrow so you are not scrambling inside the 45-day window. And if you are selling in the last quarter of the year, talk to your CPA about extending your return so the tax-return rule does not quietly shorten your 180 days.

The deadlines are rigid, but they are also predictable. The investors who miss them almost always did so because they treated “about 45 days” and “roughly six months” as soft targets. They are not.

Sources

IRS, Like-Kind Exchanges, Real Estate Tax Tips
IRS, Instructions for Form 8824, Like-Kind Exchanges
IRS, About Form 8824

Frequently Asked Questions

Do the 45-day and 180-day periods start on different dates?

No. Both start on the same day, the date your relinquished property closes and transfers. The 45-day identification window runs inside the 180-day replacement period, so it is 180 days total, not 225.

Can I get an extension on the 45-day or 180-day deadline?

Generally no. Title problems, financing delays, and slow escrows are not grounds for an extension, and the periods are not pushed back for weekends or holidays. The main exception is a federally declared disaster covering your property or principal place of business, where the IRS can grant relief.

What is the tax-return deadline rule?

Your replacement period ends on the earlier of 180 days after the sale or the due date of your tax return (including extensions) for the year you sold. If you sell late in the year and file your return early, you can accidentally end your exchange before 180 days. Filing an extension preserves the full window.

What happens if I miss a deadline?

The exchange fails. The gain you were deferring becomes recognized in the year of the sale, and you owe the capital gains tax, any unrecaptured Section 1250 gain, and any net investment income tax that applies, plus state tax.

Does the replacement property have to be identified in writing?

Yes. The identification must be signed by you and delivered in writing to your qualified intermediary (or another non-disqualified party to the exchange) by midnight of day 45, and it must describe the property clearly enough to be unambiguous.