1031 Exchange Deadline Calculator

Section 1031 of the Internal Revenue Code gives investors two non-negotiable deadlines after closing the sale of a relinquished property. Day 45 is the deadline to identify replacement candidates in writing to your Qualified Intermediary. Day 180 is the deadline to actually close on one of those candidates. Both clocks start on the day after closing and run in calendar days — weekends and federal holidays included.

The two deadlines run concurrently, not sequentially. You do not get 45 days to identify and then another 180 days to close. If you close the sale on June 1, your identification deadline is July 16 and your exchange completion deadline is November 28 — period.

The 180-day window is actually capped at the earlier of 180 days OR the due date of your tax return (including extensions) for the year of the relinquished sale. If you close on October 15, your 180th day is April 13 — but your tax return is due April 15. Without an extension, your effective deadline shrinks to April 14.

Most investors filing late-year exchanges automatically file Form 4868 for a six-month extension. That pushes the return deadline to October 15, restoring the full 180 days. Talk to your CPA before the original return due date — once you've filed, you've forfeited the rest of the 180-day window.

Closing date: March 10. The 45-day identification deadline is April 24. The 180-day exchange completion deadline is September 6. The exchange falls in the same tax year as the sale, and the return isn't due until April 15 of the following year, so the tax-filing cap doesn't apply. The investor has the full 180 calendar days.