1031 exchange deadline calculator

How the two deadlines work

You have 45 days after the sale closes to identify replacement property in writing, and 180 days after the sale to receive it. Both clocks start the same day, run at the same time, and count calendar days. The 180 days are not 45 plus 180. If you take all 45 days to identify, you have 135 left to close.

The rule is in the statute, IRC 1031(a)(3), and the details are in Treas. Reg. 1.1031(k)-1(b). The identification period ends at midnight on day 45. The exchange period ends on day 180 or on the due date of your tax return for the year of the sale, counting extensions, whichever comes first.

The tax return catch

If your sale closes late in the year, your return is due before day 180. Without an extension, the exchange period ends on the return due date and you lose the rest of the 180 days.

For a calendar-year individual, any sale that closes after Oct 17, 2026 runs into April 15. Here is the last closing date in 2026 that still gets the full 180 days without an extension, for each kind of filer:

Who files	Return due	Last 2026 closing with a full 180 days	Extension form	Extended due date
Individual or couple (Form 1040)	Apr 15, 2027	Oct 17, 2026	Form 4868	Oct 15, 2027
Trust or estate (Form 1041)	Apr 15, 2027	Oct 17, 2026	Form 7004	Sep 30, 2027
Partnership or LLC (Form 1065)	Mar 15, 2027	Sep 16, 2026	Form 7004	Sep 15, 2027
S corporation (Form 1120-S)	Mar 15, 2027	Sep 16, 2026	Form 7004	Sep 15, 2027
C corporation (Form 1120)	Apr 15, 2027	Oct 17, 2026	Form 7004	Oct 15, 2027

File the extension by the original due date; a late extension does nothing. And if a replacement is still pending when your preparer is ready to file, say so before anything gets filed.

Fiscal-year filers count from the end of their own tax year. The table assumes a calendar year.

What counts as identifying a property

Identification is a written document, signed by you, that names the replacement property clearly enough to find it: a street address, a legal description or a distinguishable unit name. It has to reach someone involved in the exchange who isn't a disqualified person, which in practice means your qualified intermediary, by midnight of day 45. A property you actually close on within the 45 days counts as identified without a letter.

You can change your list as often as you like until the 45 days end. After that the list is locked.

How many properties you can name

The regulations give you three ways to identify. You only need to meet one of them.

Rule	What you can identify	The catch
Three-property rule	Up to 3 properties of any value	None. Value doesn't matter.
200% rule	Any number of properties whose total fair market value is no more than 200% of what you sold	Sold $1.5 million? Your list can total $3 million, not a dollar more
95% exception	Any number at any value	You must actually acquire 95% of the total value you identified, or the whole identification fails

If you name more than three properties and blow past 200%, you are treated as having identified nothing, unless you meet the 95% exception. The whole list is void, not just the extra property. DST investors who name several offerings as backups are the usual case for checking this: add up the values before you send the letter.

Weekends, holidays and disasters

Nothing in the regulations moves a deadline off a weekend or holiday. The calculator flags dates that land on a Saturday, a Sunday or a federal holiday so you know to finish early; your intermediary and title company may be closed.

The one exception is a disaster postponement. When the IRS grants relief for a federally declared disaster under IRC 7508A, Rev. Proc. 2018-58 lets the relief reach 1031 deadlines too: a deadline that falls in the relief window moves to the later of 120 days out or the end of the relief period, but never past the extended due date of your return or one year. It applies only if you or the property are in the covered area, or the people you need, like your intermediary or lender, are. Check the IRS disaster relief page for your state before counting on it.

If you miss a deadline

Miss day 45 with nothing properly identified and the exchange fails. Your intermediary releases the cash and the sale is taxed like any other. If the sale closed in one year and the money comes back to you the next, the regulations generally let you report the gain in the year you receive the cash, which can push the tax bill out by a year. The capital gains calculator shows what that bill looks like.

Sources

• 26 U.S.C. 1031(a)(3), the 45- and 180-day periods.
• 26 CFR 1.1031(k)-1, paragraphs (b) (periods), (c) (identification) and (j)(2) (installment reporting when an exchange fails).
• Rev. Proc. 2018-58, disaster postponements and section 1031.
• Return due dates: Form 4868, Form 7004 and the instructions for Forms 1065, 1120-S, 1120 and 1041.