You can estimate an STR's year 1 bonus depreciation before making an offer using purchase price, land ratio, square footage, year built, and interior finish quality. DepreciMax runs this analysis in under 5 minutes for $99 — giving you the same inputs your CPA needs before you're locked in.
Running STR depreciation before purchase is one of the few diligence moves that pays for itself the same week. Most short-term rental buyers calculate their year 1 deduction in April of the year after they close, when the number is already baked in. By then there is nothing to negotiate. The property is what it is, the price is what you paid, and the depreciation number is whatever the property happens to produce.
The investors who consistently outperform run the depreciation analysis before they submit a contract. They factor the year 1 deduction into their effective acquisition cost, set their offer floor accordingly, and walk into closing knowing precisely what their CPA will deliver in April. This article walks through the 5-step process for running that pre-offer check, including how DepreciMax handles it in under 5 minutes. For the market-level baseline, our 2026 STR Bonus Depreciation Market Study ranks 197 US STR markets by median bonus-eligible share of purchase price.
Don't make the offer until you know the number
Upload listing photos and we'll return a line-item year 1 bonus depreciation estimate closely calibrated to a formal cost seg study. $99, one time, 5 minutes.
Run a Bonus Depreciation Analysis →Why depreciation math belongs at the offer stage, not tax time
Year 1 bonus depreciation on an STR can range from 12% to 32% of the purchase price, depending on land ratio, finishes, outdoor amenities, and how furnishings convey. On a $600,000 STR that is the difference between $72,000 and $192,000 in first-year deductions — a $120,000 swing. That swing changes your after-tax acquisition cost by roughly $44,400 at a 37% bracket.
If you do not know which side of the range your specific property sits on, you cannot underwrite the deal correctly. You either overpay because you assumed the high end, or you walk away from a great deal because you assumed the low end. The point of a pre-purchase cost segregation estimate is to remove that uncertainty before the contract goes hard. See how DepreciMax works for the full methodology.
The 5 inputs you need before you run the numbers
All five fields below are pulled from the listing or the county assessor record. None require a property visit. None require a contract. You can run the analysis on any active listing in 5 minutes.
| Input | Where to find it | Why it matters |
|---|---|---|
| Purchase price | Listing | The denominator on every depreciation percentage. Drives basis directly. |
| Land value ratio | County assessor / aggregated parcel data | Land is not depreciable. A 35% land ratio cuts your basis nearly in half versus a 15% ratio. |
| Square footage | Listing | Drives 5-year personal property allocation and 39-year structural shell. Larger footprints = more depreciable surface. |
| Year built | Listing | Affects finish era. 2015+ builds typically have higher 5-year personal property percentage from modern fixtures and appliances. |
| Interior finish quality | Listing photos | The biggest single swing factor. Custom cabinetry, stone, premium appliances, and FF&E all classify as 5-year property at 100% bonus rate. |
If you are evaluating a listing without good photos, the analysis becomes much weaker. Eight to nine photos covering kitchen, primary bath, living area, bedrooms, and outdoor amenities give the AI enough signal to classify finishes with confidence. The STR investor guide details which photos matter most.
Step-by-step: how to run a DepreciMax report on a listing
The full pre-offer process takes about 5 minutes. The output is a line-item bonus depreciation report by IRS asset class — the same format your CPA needs to populate Form 4562 after you close. Use the 5 steps below.
Capture the listing details
Save the Realtor.com or Zillow listing URL, plus 7–9 of the best interior and exterior photos. Photos should cover the kitchen, primary bath, living area, bedrooms, and any outdoor amenities. On the on-market flow you can paste just the listing URL and DepreciMax auto-fetches the photos directly from the listing.
Confirm purchase price and basic specs
Note your intended offer price, the square footage, year built, and bed/bath count. These five fields establish the depreciation basis. The intended offer price (not list price) is what you want in the calculation — if you plan to negotiate, run two scenarios.
Pull the land value ratio
DepreciMax pulls this automatically from aggregated county-assessor land value data and the FHFA zip-level dataset. You can verify by visiting the county parcel viewer and dividing land value by total assessed value. For condos the assessor often books land at zero, which means the entire basis depreciates. For mountain cabins land ratio is typically 10–18%. For coastal and urban properties it can reach 40%+.
Run the DepreciMax report
Upload the photos, paste the listing URL, and confirm property details. The AI analyzes finishes, fixtures, FF&E, and outdoor amenities by IRS asset class — separating 5-year personal property, 15-year land improvements, and 39-year structural shell. The report runs in approximately 5 minutes and costs $99 one time.
Use the number in your underwriting
Take the year 1 deduction estimate to your CPA. Apply your marginal tax bracket to get the after-tax cash recovery. Reduce your effective acquisition cost by that amount, then rerun your IRR model. The new after-tax cost is your real offer-floor reference. Bake it into your contract terms before you submit.
Ready to run the check on a specific listing?
Run a Bonus Depreciation Analysis →What to do with the number once you have it
The output is only useful if you actually integrate it into the deal. Three concrete uses cover most of what a sophisticated STR investor does with the report.
- CPA conversation. Email the report PDF to your CPA the same day. Ask them to confirm material participation strategy (you need 100+ hours and more than anyone else, or qualify under the 500-hour test). Confirm state conformity. Lock in the depreciation method on Form 4562.
- Tax bracket modeling. If the year 1 deduction is large enough to push you below a bracket threshold, the marginal benefit is amplified. A $150,000 deduction that drops you from 37% to 35% saves more than the linear math suggests because of the bracket boundary.
- Deal floor-setting. Reduce your purchase price by the after-tax deduction value (deduction × marginal rate). That is your effective acquisition cost. Compare against rent comps to determine whether the deal hits your cap rate threshold. If yes, this is your max bid; if no, walk.
For the full year 1 dollar math at three price points, see how much you can write off in year 1 on an STR. The companion piece covers the $400k / $600k / $900k math in detail.
Red flags that reduce your write-off
Not every property is a strong bonus depreciation candidate. The pre-offer check is most valuable when it reveals a red flag — because those are the deals where you adjust your offer downward or walk entirely. Watch for these four.
High land ratio (30%+). Coastal lots, urban infill, and parcels with significant view value often book 35–55% land. Your depreciable basis drops dramatically. A property with 45% land ratio produces half the deduction of an equivalent 15% land ratio property.
Older builds without renovation. Pre-1990 properties with original finishes have low 5-year personal property allocations because the FF&E and fixtures are minimal-grade. Renovation history matters — a 1980 cabin gut-renovated in 2022 looks like a 2022 property for asset classification purposes.
Furnishings do not convey. If the seller is taking the furniture, you lose $40,000–$90,000 of FF&E that would otherwise be 5-year personal property. Negotiate furnishings into the contract or adjust your offer price downward to offset.
Minimal outdoor amenities. No pool, no hot tub, no outdoor kitchen, no fire pit, basic landscaping. 15-year land improvements collapse to driveway and walkway only. The deduction loses 5–8% of purchase price compared to a property with full outdoor build-out.
"The point of pre-purchase analysis is not to talk yourself into the deal — it is to give yourself the option to walk away with discipline." — DepreciMax benchmark commentary, 2025
When to Use a Pre-Purchase Estimate vs. a Formal Cost Segregation Study
A cost segregation estimate before buying property and a formal cost segregation study are two different tools built for two different moments in the deal. Confusing them costs investors either money or time — usually both. Understanding when each one earns its keep is the difference between underwriting well and either overpaying at the offer or leaving deductions on the table at filing.
The pre-purchase estimate costs $99 and runs in minutes from an address. Its job is to tell you, before the offer deadline, roughly what the Year 1 deduction will look like — closely calibrated to formal cost segregation studies, but derived from assessor data, listing photos, and STR-specific component ratios rather than a site visit. You use it to underwrite the deal, set your offer floor, brief your CPA, and decide whether a full study is even worth commissioning after closing. It is fundamentally a decide-whether-to-buy tool.
The formal cost segregation study costs $5,000–$15,000 and takes 4–8 weeks. It requires an engineered-quality analysis with a site visit, a component-by-component breakdown, and IRS-audit-defensible documentation. Its job is to maximize your defensible Year 1 deduction for filing — after you already own the property. It is fundamentally a maximize-what-you-can-file tool. For a full breakdown of what a formal study actually costs, the pricing varies with property size, complexity, and provider tier.
| Pre-Purchase Estimate | Formal Cost Segregation Study | |
|---|---|---|
| Cost | $99 | $5,000–$15,000 |
| Timing | Before the offer | After closing, before filing |
| Purpose | Decide whether to buy | Maximize the defensible deduction |
| Deliverable | Year 1 estimate + component ranges | Engineered study with site visit documentation |
| When to use | Any active listing you might offer on | Any property you already closed on where the deduction justifies the fee |
| When not to use | Filing (not audit-defensible on its own) | Screening deals (too slow, too expensive) |
The two tools are complementary, not competitive. A $99 cost segregation before buying rental property estimate is what tells you whether the $5,000+ formal study is worth commissioning at all. If the estimate shows a $140,000 Year 1 deduction on a $600,000 STR, the formal study easily pays for itself several times over. If the estimate shows a $48,000 deduction because the property is a high-land-ratio coastal lot with minimal amenities — and see also the 30% land rule myth for why that ratio isn't as fixed as most investors assume — you save the $5,000 by skipping the formal study and using standard depreciation methods instead.
Cost seg firms are downstream partners in this workflow, not competitors. The estimate exists to route the right properties to them. Every investor who runs a pre-purchase estimate and then commissions a formal study post-close is a customer both tools deserve. What no investor should do is skip the estimate, buy blind, then discover at filing time that the deduction wasn't large enough to justify the study — or worse, that the deal itself didn't underwrite. The estimate is the cheap insurance that makes the expensive study a rational spend.
Frequently Asked Questions
Can I do an STR depreciation check before purchase with a spreadsheet?
A spreadsheet can get you the basic structure but not the property-specific bonus-eligible percentage, which is where the real money is. The 5-year and 15-year asset classification depends on what is actually present in the property — pools, FF&E, finish quality, outdoor features. A spreadsheet defaults to a generic 22% multiplier and is typically off by 30–50% on either side of the real number for a specific property.
How accurate is a pre-purchase bonus depreciation estimate?
DepreciMax pre-purchase estimates are closely calibrated to formal cost segregation studies on the same property. The methodology is the same engineering-based asset classification, just applied to listing photos and assessor data instead of an on-site inspection. For pre-offer underwriting, that is more than sufficient accuracy to set your offer floor and brief your CPA.
Do I need actual photos to run a pre-offer depreciation check?
Yes. The AI analyzes specific visible features in the photos — flooring type, cabinetry, countertops, appliances, lighting fixtures, outdoor amenities. Without photos, the report falls back to market-average defaults, which defeats the purpose. Listing photos from Realtor.com or Zillow are sufficient — the on-market flow auto-fetches them from the listing URL so you don't even need to download.
Will my offer price reflect the depreciation number?
It should. The year 1 deduction is real after-tax cash you recover. On a $600,000 STR generating $132,000 in year 1 deductions at a 37% marginal rate, you recover roughly $48,840 after April. That changes your effective acquisition cost from $600,000 to roughly $551,000, which directly impacts your IRR and your maximum acceptable offer price.
Can my CPA review the DepreciMax report before I file?
Yes. The DepreciMax report produces a line-item asset classification by IRS class life — exactly the format your CPA needs to populate Form 4562. Most CPAs find the report directly usable as the depreciation schedule support documentation. For audit defense on properties over $1.5M, a formal cost segregation study is still recommended in addition. See when to use a formal cost seg study vs. DepreciMax.
Can I get a cost segregation estimate before I make an offer on an STR?
Yes. Pre-purchase cost segregation estimates are the entire purpose of tools like DepreciMax — you enter an address and get a Year-1 depreciation estimate in minutes, before your offer deadline. The estimate uses county assessor data, comparable property analysis, and STR-specific component ratios to produce a number closely calibrated to formal cost segregation studies (which cost $5,000–$15,000 and take 4–8 weeks post-close). The pre-purchase estimate is what lets you underwrite the deal correctly. You know your after-tax return before you commit. If the number justifies it, you commission a formal study after closing to maximize the defensible deduction for filing. If the number doesn't justify a $5K study, you save the money.
Get the pre-offer number in 5 minutes
Bonus Depreciation Analysis on any active STR listing — closely calibrated to a formal $5,000–$8,000 cost seg study. $99 one-time, runs in your browser.
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