OZ Deadline Calculator

Edited by Barrett Linburg Updated: September 6, 2026

Change note: Corrected day-one counting and pass-through inputs.

OZ Deadline Calculator: Find Your 180-Day Window

Calculate a raw calendar result from the facts entered. For a direct gain, the recognition date is day one and the 180th day is 179 days later. For an owner of a partnership or S corporation that has not deferred eligible gain, the calculator can show the entity year-end and unextended-return-due-date alternatives in Treas. Reg. section 1.1400Z2(a)-1(c)(8)(iii). It does not determine eligibility, relief, or tax-payment deadlines.

180-Day Deadline Calculator

This tool calculates raw calendar results only. Nothing is sent to a server.

A K-1 receipt is not itself a start date.
For a direct gain, day one of the 180-day period.

Notice 2026-40 section 4.02 is announced transition guidance for timely pre-2027 eligible gain invested from January 1, 2027. It is not final regulations. Confirm the election, actual entity dates, and any weekend, holiday, or disaster relief with a qualified adviser.

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