The familiar “180-day rule” has an important qualifier.
The IRS instructions provide that replacement property generally must be received by the earlier of the 180th day after transfer of the relinquished property or the due date of the taxpayer’s return, including extensions, for the year of transfer.
That means a simple online date calculation can be useful for planning but should not be treated as the final legal deadline for every taxpayer. Filing calendar, extensions and transaction-specific relief can matter.
Work backward from closing feasibility.
Due diligence, lender underwriting, third-party reports, title, insurance and entity documentation can compress the usable portion of the exchange period. Replacement-property strategy should be paired with a closing-readiness strategy.
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