Estate 706 Deadline & Portability Clock by ReadyStack

Enter the date of death: get the 9-month Form 706 due date, the Form 4768 extended date, the earliest Pay.gov closing-letter request date, the five-year late-portability window, and the 2026 $15,000,000 exclusion math - in the browser tab you already have open.

1. Unzip this folder somewhere permanent.
2. Open chrome://extensions and turn on Developer mode (top right).
3. Click Load unpacked and pick the unzipped folder.
4. Pin the icon and click it.

Works in Chrome, Edge, Brave and any Chromium browser (Manifest V3).

• Exclusion locked to the year of death — Applies the IRC 2010(c)(3) basic exclusion for the decedent's year of death - $15,000,000 for 2026 under OBBBA section 70106 and Rev. Proc. 2025-32, $13,990,000 for 2025 - instead of the repealed sunset figure that pre-2025 sources still quote.
• Nine-month due date and the Form 4768 extension — Counts the IRC 6075(a) nine-month Form 706 due date from the date of death and, when the automatic Form 4768 extension is elected, the six-month extended date, then shows days remaining from today.
• Earliest closing-letter request date — The IRS asks requesters to wait at least nine months after Form 706 is filed before ordering Letter 627 on Pay.gov; this dates that window from the actual filing date so nobody pays the user fee early.
• Five-year late portability election window — When the gross estate is under the filing threshold, Rev. Proc. 2022-32 allows a late DSUE portability election up to the fifth anniversary of death; the tool dates that anniversary and says when it does not apply.
• Month-one cost of slipping the date — Prices the IRC 6651(a)(1) failure-to-file addition - five percent of the tax for each month or fraction of a month - so the deadline has a dollar figure next to it, not just a date.
• CSV checklist export and deadline alarms — The paid layer writes the dated checklist to a .csv you can drop in the client file and sets Chrome alarms ahead of each date, so the clock keeps running after the tab is closed.

| You type | |
|---|---|
| Date of death | default 2026-03-15 |
| Gross estate + adjusted taxable gifts | default 18400000 |
| Marital, charitable and debt deductions | default 1200000 |
| DSUE ported from a predeceased spouse | default 0 |
| Automatic 6-month extension elected (Form 4768) | default True |
| Date Form 706 was actually filed | default 2026-12-10 |
| Today | default 2026-09-14 |

| It answers | |
|---|---|
| Basic exclusion for the year of death | USD |
| Exclusion + DSUE available | USD |
| Taxable estate after deductions | USD |
| Estimated federal estate tax (40% of the excess) | USD |
| Form 706 due (9 months, IRC 6075(a)) | |
| Extended due date (Form 4768) | |
| Days left to the operative deadline | days |
| Earliest closing-letter request (Pay.gov, $56) | |
| Late portability window closes (Rev. Proc. 2022-32) | |
| Month-one failure-to-file addition (IRC 6651(a)(1)) | USD |

Permissions requested: storage, downloads, alarms, notifications


Free: the calculation in the popup, no key, no limit. Full version ($60): download the result as .csv and deadline reminders - one licence key per person or team seat. Get it: https://buy.polar.sh/polar_cl_YtqCQevdtAAEQeezD2b3ar2OEcxcI0xwnkXEn25tSMY