A 1031 exchange lives or dies on two dates. Miss either one and the exchange collapses, with the full tax bill becoming due in that tax year. The rules are strict, counted in calendar days, and almost never extended. This tool removes the guesswork by calculating both deadlines from the only date that matters: the day your relinquished property closes.
The two deadlines that govern every exchange
The single most misunderstood point about 1031 timing is this: both clocks start on the same day and run at the same time. The day your sale closes is Day 0. From that point you have 45 calendar days to identify replacement property and 180 calendar days to close on it. The 45-day window sits inside the 180-day window, they are not sequential, and you do not add them together.
The 45-day identification rule
Within 45 calendar days of closing, you must identify your replacement property or properties in writing and deliver that identification to your Qualified Intermediary. Weekends and holidays count. There is no grace period and no extension outside of a federally declared disaster. After Day 45, your identification list is locked, you can only buy what you named in time.
The three identification rules explained
The IRS lets you choose one of three rules when identifying replacement property by Day 45. You pick whichever fits your strategy.
The Three-Property Rule
Identify up to three potential replacement properties of any value, and buy one, two, or all three. This is the most common approach and works for most investors who have a clear short list. No value cap applies.
The 200% Rule
Identify any number of properties, as long as their combined fair market value does not exceed 200% of the value of the property you sold. This suits investors spreading proceeds across many smaller assets.
The 95% Rule
Identify any number of properties with no value cap, but you must actually acquire at least 95% of the total value you identified. This is the most aggressive and least forgiving rule, used rarely and usually only with professional guidance.
The 180-day completion deadline
You must close on your replacement property within 180 calendar days of Day 0. But there is a trap that catches end-of-year sellers: your exchange period ends at 180 days OR the due date of your tax return for that year, whichever is earlier. If you sell in, say, November, your tax return due date in mid-April arrives before Day 180, cutting your window short. The fix is simple, file a tax extension to preserve the full 180 days, but you have to know to do it.
Your exchange checklist, step by step
- Engage a Qualified Intermediary before closing. You cannot set up the exchange after you have closed, and you cannot touch the proceeds yourself.
- Close the relinquished property (Day 0). This starts both clocks.
- Identify replacement property in writing by Day 45, following one of the three rules above.
- Sign the purchase contract for your chosen replacement property.
- Close on the replacement property by Day 180 (or your tax filing due date, whichever is earlier).
What happens if you miss a deadline
There is no partial credit. Miss the 45-day identification or the 180-day closing and the exchange fails entirely. The sale reverts to a fully taxable event, and you owe federal capital gains, depreciation recapture of up to 25%, the 3.8% NIIT if applicable, and state tax, on the full gain, in that tax year. That is precisely why the dates this tool produces are worth taking seriously, and why most investors engage a QI early to keep the timeline on track.
Frequently asked questions
Do weekends and holidays count toward the 45 and 180 days?
Yes. Both periods are counted in calendar days with no extensions for weekends or holidays. If a deadline falls on a weekend, it does not roll to the next business day.
Can the 45-day or 180-day deadline be extended?
Only in narrow cases. The IRS may grant extensions for taxpayers affected by federally declared disasters. Outside of that, the deadlines are absolute and missing either one disqualifies the exchange.
What if Day 180 falls after my tax filing deadline?
Your exchange period ends at 180 days or the due date of your tax return for that year, whichever is earlier. If you close late in the year, you often must file a tax extension to use the full 180 days.
Can I change my identified properties after Day 45?
No. Once the 45-day identification window closes, your list is locked. You can only acquire properties that were properly identified within the first 45 days.
Do the 45 and 180 day clocks run at the same time?
Yes. Both clocks start on the same Day 0, the relinquished property closing, and run concurrently. The 45-day window sits inside the 180-day window; they are not added together.
This tool and article are for informational and planning purposes only and do not constitute legal, investment, or tax advice. 1031 exchange rules are complex and subject to change. Always consult a qualified tax advisor, attorney, and Qualified Intermediary before acting.
