Deadline calculator
Your Sale
Day 0 is the closing date of the property you're selling (or plan to sell). Results update instantly.
Want the tax math too? Use the 1031 tax savings calculator.
Your Deadlines
Pick your closing date to see your exact 45-day and 180-day deadlines.
How the 45-day and 180-day deadlines actually work
Day 0 is the closing date of your relinquished property. From that single date, two clocks run at the same time:
- Day 45 — identification deadline. By midnight of day 45 you must deliver a signed, written identification of your replacement properties to your qualified intermediary. Most investors use the 3-property rule; the 200% and 95% rules are the alternatives.
- Day 180 — exchange deadline. You must close on the replacement property by day 180. Not "be in contract" — closed, title transferred.
The periods run simultaneously, not back to back. Identifying on day 45 leaves you only 135 days to close. Full walkthrough in the 1031 exchange timeline guide.
The tax-return trap (late-year closings)
IRC §1031 gives you 180 days or until the due date of your tax return for the year of the sale — whichever comes first. Close in November and file your return in February? You just cut your own exchange period short. The fix is simple — file an extension (Form 4868) — but only if you know to do it. The calculator above flags this automatically for late-year closings.
What can't save you
Financing delays, a buyer walking, title issues, illness — none of them extend the deadlines. The only postponement is IRS disaster relief under Rev. Proc. 2018-58, when an IRS notice covers your exchange. This is why the single best predictor of a successful exchange is how early you start shopping for the replacement — ideally before you close the sale.
What this calculator assumes, and what it cannot tell you
- Day 0 is the closing date you enter. Under Treas. Reg. §1.1031(k)-1(b)(2), both periods begin on the date you transfer the relinquished property. If more than one property is transferred on different dates, the periods run from the earliest transfer; enter that date.
- Calendar days, no rollover. Day 45 and day 180 are counted in calendar days and do not move to the next business day.
- Tax-return due date. The late-year warning assumes a calendar-year individual return due April 15 of the following year. Partnerships and S corporations (March 15), C corporations, and fiscal-year filers have different dates; the warning may fire too late or too early for them. Filing an extension (Form 4868 for individuals) restores the full 180 days because the cap is the due date including extensions. Details: the exchange period and your tax-return due date.
- Disaster relief is not applied. The calculator never adds IRS disaster postponements. Whether Rev. Proc. 2018-58 Section 17 postpones your dates depends on the specific IRS release, on your sale having closed on or before the disaster date, and on your qualifying as an affected taxpayer or meeting a listed difficulty test. Read how disaster relief can postpone 1031 deadlines and confirm with your intermediary and CPA; this page does not make that determination.
- Reverse and improvement exchanges run on parallel 180-day rules under Rev. Proc. 2000-37 that this calculator does not model.
Sources: Instructions for Form 8824 · Treas. Reg. §1.1031(k)-1 · Rev. Proc. 2018-58. Educational tool, not tax or legal advice.