How the 1031 clocks actually work

When you sell property in a 1031 exchange, two deadlines start the day after your relinquished property transfers:

45 days to identify. You must identify potential replacement property in writing, signed and delivered to your qualified intermediary or another party to the exchange. Identifying it in your head, or telling your agent, doesn't count.

180 days to close. You must receive the replacement property by the 180th day — or by your tax return due date for the year of the transfer, if that comes first.

The single most common misunderstanding: these run concurrently, not sequentially. Day 180 is 180 days from your closing, not 45 plus 180. You do not get 225 days.

The second most common: these are calendar days with no weekend or holiday extension. If day 45 lands on a Sunday, the deadline is that Sunday.

The late-year closing trap

If you close in the fourth quarter, your 180 days may be shorter than 180 days. The exchange period ends on the earlier of the 180th day or the due date of your tax return for the year of the transfer, including extensions.

Close on November 15 and your raw 180th day falls in mid-May — but your return is due April 15, so your exchange period ends then instead, costing you roughly a month. Filing an extension for that tax year restores the full 180 days, but the extension has to be filed before the original due date passes. This is a question for your CPA the week you close, not the week you're scrambling for a replacement property.

The identification rules

Your written identification has to satisfy one of three rules:

Three-property rule. Identify up to three properties of any value. Most exchangers use this.

200% rule. Identify any number of properties as long as their combined fair market value doesn't exceed 200% of what you sold.

95% rule. Identify any number of properties of any value, but you must actually acquire at least 95% of the total value identified. Rarely used, and unforgiving.

Identify properties clearly enough to be unambiguous — a street address or legal description, not 'a retail building in Columbus.'

What happens if you miss a deadline

There are no extensions for missing the 45- or 180-day deadlines in the ordinary course. A missed deadline means the exchange fails and the gain is recognized in the year of the original sale.

One narrow exception: the IRS periodically grants deadline relief to taxpayers in federally declared disaster areas. That relief is announced case by case, and you'd need to confirm your situation qualifies.

If your exchange has failed or is heading that way, the gain doesn't have to land all in one year. A structured installment sale under IRC §453 spreads recognition across a schedule of payments funded by a rated insurance carrier — no replacement property, no deadlines. The timing matters, though: the structure has to be in place before the sale proceeds reach you, so the earlier in the exchange window that conversation happens, the more options exist.

What this calculator doesn't do

It computes calendar deadlines from the date you enter. It doesn't know whether your identification was properly written and delivered, whether your replacement property qualifies as like-kind, whether a reverse or improvement exchange changes your timeline, or whether disaster relief applies to you. Return due dates here assume an individual calendar-year filer (April 15, or October 15 with an extension); entities on other fiscal years have different filing dates. Confirm your actual dates with your qualified intermediary — they're the party holding the deadline, and they track it for you.

Frequently asked questions

When do the 45 and 180 days start?

The day after the relinquished property transfers. Both periods start on the same day and run concurrently — day 180 is 180 days from closing, not 45 days plus 180 days.

Do 1031 deadlines extend if they fall on a weekend or holiday?

No. Unlike many tax deadlines, the 45-day and 180-day periods are calendar days with no rollover. If your deadline falls on a Saturday, it's due that Saturday.

Can my 180-day period be shorter than 180 days?

Yes. The exchange period ends on the earlier of the 180th day or your tax return due date for the year of the transfer. Late-year closings are commonly cut short unless you file an extension for that tax year.

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

The exchange fails and the gain is recognized in the year of the original sale. A structured installment sale can sometimes still spread that gain across future payments, but it has to be arranged before the proceeds reach you.

Sources

Last reviewed: August 10, 2026.

This tool is for general education only and is not tax, legal, or investment advice. 1031 exchange deadlines are fact-specific. Confirm your dates with your qualified intermediary and tax advisor before acting.