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Intermediate tutorial

Cost Seg on an Airbnb With the 7-Day Rule (a Walkthrough)

How an STR with an average rental period of 4 days clears the §469(c)(2) carve-out, why 8-day averages get treated as passive, and a worked example at 100% bonus.

Cost Seg on an Airbnb With the 7-Day Rule (a Walkthrough)

This tutorial covers a single mechanic: the §469(c)(2) average-rental-period carve-out for short-term rentals. The IRC §469 passive-activity-loss rules generally suspend a year-1 cost-seg deduction on a rental property until the property generates passive income or the owner sells. The carve-out is the door that lets a year-1 deduction land against active wages — but only if the property meets the rental-period test and the owner materially participates. The calculator validates the rental-period prong via the avg_rental_days field; the participation prong is the property owner's own facts.

The §469(c)(2) carve-out, in code language

IRC §469(c)(2) defines a "rental activity" as one where payments are principally for the use of tangible property. Treas. Reg. §1.469-1T(e)(3)(ii) then carves six exceptions out of "rental activity" — the most relevant one for short-term rentals is (A): the average period of customer use is 7 days or less. When that exception applies, the activity is no longer a §469 rental activity. It is a trade or business. Material participation under §469(h) determines whether the resulting losses are passive or non-passive — and material participation by an active host in a small portfolio is generally achievable.

The threshold is "average period of customer use," not median, not modal. It is the total rental days divided by the number of separate stays in the year. A property rented for 200 nights across 50 stays averages 4 days per stay. The same property rented for 200 nights across 22 stays averages roughly 9 days per stay, and the carve-out fails — that property is treated as an LTR for §469 purposes regardless of how it is marketed.

What the calculator does with avg_rental_days

The engine sets pal_gated=False (deduction usable in the year of acquisition) when:

It sets pal_gated=True (deduction suspended on Form 8582 until passive income or sale) when:

pal_gated=True flips the results UI from a single "year-1 tax savings" hero number to a two-card layout — "deduction generated" and "cash impact subject to PAL." The cash impact in the year of acquisition can be as low as ~$0 until the property produces passive income.

Worked example — STR with 4-day average

A property owner buys a 4-bedroom Galveston short-term rental in May 2026 for $620,000 with $90,000 allocated to land, leaving $530,000 of depreciable basis. The owner self-manages, runs the property year-round, books mostly weekend stays, and ends 2026 with 220 rented nights across 55 separate guest stays — a 4-day average.

Base STR allocation per BASE_PERCENTAGES: 13% to 5-year, 1% to 7-year, 8% to 15-year. With no per-item upgrades, that is roughly 22% of $530,000 = $116,600 of personal-property basis. At 100% bonus depreciation under IRC §168(k)(6) (OBBBA permanent rate), the full $116,600 hits as a year-1 deduction. Add the partial-year mid-month building S/L on the remaining $413,400 at 27.5 years (May placement, 7.5 months in service) and the year-1 deduction comes in around $129,000.

At a 32% federal bracket, that is roughly $41,300 of year-1 federal tax effect. Because avg_rental_days=4 is at or below 7, the engine reports pal_gated=False and the calculator shows the headline number rather than the two-card layout. Material participation under §469(h) is the owner's separate burden — for a self-managed Airbnb that touches 100+ hours of work per year and exceeds anyone else who works on the property, the standard tests in §469(h)(1)(1) through (7) tend to be reachable. It is not automatic; a CPA review is prudent.

Try a 4-day-average STR estimate →

Worked example — same property, 8-day average

Same purchase, same basis, same allocation — but the owner books mostly week-long stays and ends the year at 220 nights across 26 stays, an 8.5-day average. The engine flags pal_gated=True with a reason citing the §469(c)(2) test:

"Average rental period entered as 8 days. The §469(c)(2) short-term-rental carve-out requires an average of 7 days or less. With longer-period rentals, the activity is treated as passive — the year-1 deduction is typically reported on Form 8582 and suspended until you have passive income or sell the property."

The deduction does not vanish. It is suspended under §469(b) and carries forward indefinitely, releasing when the property has passive income or in full when the owner sells in a fully taxable transaction. For an owner counting on the year-1 cash impact, the difference between a 6.8-day and an 8.5-day average is the difference between a current-year tax effect and a deferred one.

See how an 8-day average changes the same property →

§1245 recapture is the second shoe

Short-term rentals are flipped at higher rates than long-term holds. Reclassified personal property (5-year and 15-year buckets) is §1245 — accumulated depreciation is recaptured as ordinary income on disposition, not §1250's 25% unrecaptured cap-gain rate. The calculator surfaces a recapture warning whenever the property type is STR and the planned disposition is anything shorter than 5 years. The warning is not a recommendation against the strategy; it is the second number to bring to the CPA conversation alongside the year-1 effect.

Citations

Disclaimer. This tutorial describes general federal tax concepts. TaxProtestTx (Nought Labs LLC) is a feasibility-screening tool, not tax advice or a cost segregation study. Calculator output cannot be relied on under Treasury Circular 230. Consult a qualified CPA, EA, or attorney before filing. Results are not guaranteed.

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Disclaimer. This page describes general federal tax concepts. TaxProtestTx (Nought Labs LLC) is a feasibility-screening tool, not tax advice or a cost segregation study. The calculator output cannot be relied on under Treasury Circular 230. Consult a qualified CPA, EA, or attorney before filing. Results are not guaranteed.