What happens if I get audited?

Audit support is available as an optional add-on with published written terms covering the scope of support, who assists you, and refund conditions.

Who is behind the company?

A named, U.S.-based team of engineers and tax specialists with 20+ years in the cost segregation industry. Reports are issued under Cost Seg Specialists Inc., the firm carries E&O insurance, and you can reach a real person by phone.

Cost Segregation Specialists — Instant Cost Segregation Studies from $495

Q: Is an instant cost seg study built in alignment with IRS standards?

Yes. The do-it-yourself part is simply you providing the property information, not performing the engineering analysis. Our engine applies the same methodology, cost data, and asset classifications a traditional study uses, and a U.S. specialist reviews and signs every report before it is issued under Cost Seg Specialists Inc.

Q: Can I do a study on a property I bought years ago?

Yes. With a look-back study and a Form 3115 you may be able to catch up depreciation on a property placed in service in a prior year. Ask your CPA how this applies to your filing.

Q: Why is it so much cheaper than a traditional study?

A traditional engineered study runs $5,000 to $15,000, largely for travel, manual labor, and site visits. We automate the calculation and add expert human review, so you get the same engineering for up to 90% less.

The strategy, explained

Cost Segregation 101: Front-load your depreciation. Legally. In year one.

The IRS requires you to depreciate investment property over 27.5 or 39 years. But not every component of a building ages at the same rate. A cost segregation study identifies the pieces that qualify for 5-, 7-, or 15-year depreciation — and combined with bonus depreciation, most of that can be taken in year one instead of spread over decades.

Standard depreciation

Without a study: 27.5 or 39 years

The IRS default spreads your entire property cost over 27.5 years (residential) or 39 years (commercial) in equal annual slices. You get the deduction eventually — just very slowly.

Component reclassification

A study finds what qualifies for 5, 7, or 15 years

Flooring, cabinetry, appliances, landscaping, parking lots, electrical for equipment — these have shorter IRS-defined lives. A cost seg study reclassifies them out of the 27.5/39-year bucket.

Bonus depreciation

Bonus depreciation lets you take it all in year one

Under IRC §168(k), qualifying components can be 100% deducted in the year placed in service — the One Big Beautiful Bill Act (2025) permanently reinstated 100% bonus depreciation for property placed in service after January 19, 2025. The study unlocks it — bonus depreciation does the heavy lifting.

The result

Large deductions now, not spread over decades

For a $500K property, a study might reclassify $80K–$150K of components — turning a $18K annual depreciation deduction into a $60K–$120K first-year event that offsets active or passive income.

Who it applies to

Cost segregation works for most real estate investors — if the property qualifies.

The property must be non-residential or residential rental property placed in service after 1986. Here’s who benefits most:

🏠

Short-term rental (STR) owners

Airbnb, VRBO, and other STRs frequently qualify for 5–7 year component lives on furnishings and fit-out — one of the highest-ROI scenarios for a study.

🏛

Long-term rental investors

SFRs, duplexes, and small multifamily up to $5M basis. The study pays for itself many times over when it surfaces $40K–$300K in reclassifiable components.

🏢

Commercial property owners

Office, retail, industrial, and mixed-use. 39-year depreciation makes reclassification even more impactful — the spread from 39 years to 5–15 is dramatic.

🤝

Real estate syndicates & funds

Studies are passed through to partners and investors on K-1s. Funds routinely commission studies for every acquisition above a basis threshold.

📈

New construction & major renovations

New builds and gut renovations are ideal — cost data is fresh, component allocation is clean, and the full basis is eligible from day one.

📅

Properties purchased in the last 3–5 years

You can file a catch-up study (via Form 3115) without amending prior returns — and take all prior-year missed depreciation in the current tax year as a single deduction.

⚠️

Already own the property? You don’t have to have ordered the study when you bought it. A look-back study may let you capture missed depreciation from prior years. Ask your CPA about Form 3115 and the filing steps required for your situation.

Detailed Study vs DIY Cost Seg™

Fully Engineered Study Results —
Without the Hassle, the Markup, or the Wait.

Cost segregation uses one methodology — the IRS wrote it in Rev. Proc. 87-56. Every firm uses the same RSMeans and Marshall & Swift data. The only thing that changes is whether someone bills you $15,000 to apply it, or our software does it for as little as $495.

✕ Hiring a Traditional Cost Seg Firm

✕ $5,000–$15,000 — before you know the results
✕ 3–6 weeks of proposals, site visits, back-and-forth
✕ You’re paying for their overhead, travel, and admin
✕ Same IRS methodology we use — just done by hand

✓ DIY Cost Seg

✓ From $495 — engineering-backed study, 95% less
✓ Streamlined digital process with additional service levels available when greater detail is required
✓ Built on 15,000+ completed studies — not a generic calculator
✓ IRS supportable — issued under Cost Seg Specialists Inc.

Let us help you cut out the middle man and remove the mark up

Randy Lyons 20+ years in cost segregation

What DIY Cost Seg is built on

Properties under $3M were priced out of cost segregation. We built the methodology that changed that — and we built it first.

Fully engineered cost segregation studies can run $5,000–$15,000. For many investment properties under $3M, that cost rarely pencils out — so investors leave deductions on the table. After 20 years running studies for large portfolios, I built the methodology and software to deliver IRS-supportable analysis for a fraction of the cost. DIY Cost Seg was the first to make it viable.

✓ Built in alignment with IRS audit standards — I know exactly what auditors look for, and we’ve built that into every study
✓ Powered by the same cost data your CPA uses — RSMeans, Marshall & Swift, and Rev. Proc. 87-56
✓ A process refined over 20 years and tested under IRS audits

Randy LyonsFounder · Cost Segregation Specialists

What is DIY Cost Seg?

Cost segregation software built for real estate investors — and the CPAs who serve them.

Cost segregation is an IRS-approved tax strategy that reclassifies parts of your investment property from 27.5- or 39-year depreciation into 5-, 7-, or 15-year schedules. Accelerated, it front-loads tens of thousands in deductions — legally reducing your taxable income now. Real estate investors use it to run their own study. CPA firms use it as a white-label backend to deliver studies under their own brand.

📋

Established methodology, professionally reviewed

Our software applies established methodology — Rev. Proc. 87-56, RSMeans cost data, and Marshall & Swift — used in fully engineered studies. The result is built in alignment with IRS standards and designed to be IRS supportable.

⚡

Done in minutes, not weeks

Our streamlined digital process allows most studies to be completed remotely, with additional service levels available for properties requiring greater detail or an on-site inspection.

🛡️

Issued under Cost Seg Specialists Inc.

Every study is issued under Cost Seg Specialists Inc., a professional cost segregation firm. That means your report carries professional credentials and is supported by an experienced team if questions arise.

Are you a CPA or tax advisor? Learn about our White-Label Partner Program →

How it works

Three steps from property address to a filed study

It's completely self-serve. No sales call, no proposal, no waiting on a quote. Most people finish in a few minutes, and you can save your progress and come back whenever you want.

Tell us about your investment property

Answer a few guided questions — address, purchase price, type, and when you placed it in service. Stuck on something like land vs. improvements? The built-in assistant helps. Save your progress and finish whenever you want.

A few minutes · save anytime

See your savings instantly

Our engine applies engineering-modeled cost data (RSMeans / Marshall & Swift) and current bonus-depreciation rules to estimate your first-year deduction — on screen, before you pay.

Free estimate

Download your professionally reviewed study

Pay only when you're ready. Your study runs on the engineered methodology behind 15,000+ completed studies and is issued under Cost Seg Specialists Inc. — formatted for your CPA, with optional audit support available.

CPA-ready · audit-tested methodology

Calculate My Tax Savings →

No credit card. See your number first.

See exactly what you get

An example study — and a sample report

An instant study is still a complete, CPA-ready engineered study. Here's how the numbers look on a typical short-term rental.

46× return in year one

Property (STR · single-family)

$485,000

Study cost

$495

First-year deduction

$61,400

Est. cash back @ 37%

$22,700

A $495 study produced $61,400 in first-year depreciation — about $22,700 back in real tax dollars at a 37% rate. That's roughly 46× the cost of the study, in the first year.

Already own it? You can run a study on a property you bought in a prior year and may be able to claim catch-up depreciation. Ask your CPA about Form 3115 and the filing steps for your situation.

Sample report

Cost Segregation Study

Prepared by Cost Seg Specialists Inc. · reviewed & signed

5-year property$78,200

15-year property$41,500

27.5-year (real property)$365,300

First-year deduction$61,400

📄 Download a full sample report

Why investors and CPAs choose us

An instant study, backed by 20 years of IRS-tested work

Self-serve and done in minutes, on properties up to $5M — built on the same engineered methodology that's held up under IRS audits for two decades. Investors get their deductions fast; CPAs get a study they can stand behind.

Instant — up to $5M

Full-service firms make you sit through proposal calls and wait weeks. You get an estimate in minutes on properties up to a $5M basis.

vs. KBKG's $1.5M cap

Optional audit support, in writing

Add audit support to any study, with the terms published in plain English: the scope of support, who assists you, and the refund conditions — so you know exactly what's covered before you add it.

Plain-English terms

An engineered methodology aligned with IRS standards

Your study runs on an algorithm built from 20+ years of engineered studies — the same asset classifications and cost data, applied under IRC §168(k), Rev. Proc. 87-56, and the IRS Audit Technique Guide.

Tested across 15,000+ studies

All 50 states + international

From Alaska and Hawaii to vacation rentals abroad — if it qualifies, we've studied one like it.

Including STR & LTR

The best reviews in the category

A perfect five-star average — more five-star reviews than the self-service competitors we're compared against, and trusted by CPAs and Tax Professionals nationwide.

5.0 ★ average

Up to 90% less than an engineered study

Same engineering methodology at a fraction of the cost. Software handles the calculation, so you're not paying for travel, manual labor, and site visits.

From $495 vs. $5,000–$15,000

Choose your study

One firm, three study options

Whether you want it instant or fully hands-off, the same team stands behind every report.

The sooner your study is done, the sooner the deduction can reach a return. Run it now to accelerate depreciation onto this year's filing — or ask your tax professional how a look-back study and Form 3115 may apply to a property bought in a prior year.

Calculate My Tax Savings

★ Most popular

DIY Cost Seg™

Instant self-service software. You supply the inputs; we run the engine & review.

$495+ residential · from $1,295 commercial

vs. $5,000–$15,000 engineered study

✓ Estimate on screen in minutes
✓ Reviewed & signed by a U.S. specialist
✓ Up to $5M property basis ($495–$1,495 residential, $1,295–$3,495 commercial)
✓ Optional audit support (add-on)
✓ Live phone support

Get My Report →

or run the free estimate first

Virtual Detailed Study

Our streamlined digital process handles most studies remotely, with additional service levels available when greater detail or an on-site inspection is appropriate.

$3,000+

placeholder

✓ Specialist-built, end to end
✓ Remote video walkthrough
✓ 3–5 business day turnaround
✓ Ideal for complex properties
✓ Audit support included

See If I Qualify

Fully Engineered Study

Maximum rigor for your largest assets — engineered study with site inspection.

Custom

placeholder

✓ Full engineering site visit
✓ Best for high-basis & commercial
✓ Maximum IRS supportability
✓ Dedicated specialist
✓ Audit support included

Talk to a Specialist

Not sure which fits? Run the free calculator — it points you to the right study for your investment property.

From our customers

We're the cost seg firm your CPA firm uses

Trusted by thousands of property owners — and the CPAs and tax pros who send us their clients.

5.0

★★★★★

Google Reviews

Five-star average rating

★★★★★

"I was nervous about doing this without my CPA's $8,000 study. The estimate matched almost exactly, a real person reviewed it, and my accountant signed off with no issues. Saved me thousands."

R. Martinez

STR owner · Arizona

Verified Google review

★★★★★

"As a CPA I was skeptical of an 'instant' study. Then I read the report — engineering cost data, proper class lives, the works. I now send my real estate clients here instead of the firms charging 5x."

J. Thompson, CPA

Tax advisor · Texas

Verified Google review

★★★★★

"Fast, clear, and they actually picked up the phone when I had a question. The first-year deduction was even bigger than the estimate. Already ordered my second study."

D. Kim

Multifamily investor · Florida

Verified Google review

★★★★★

"The process was unbelievably simple. I plugged in my numbers, saw the savings instantly, and had a finished study a few days later. Knocked five figures off my tax bill."

S. Patel

Rental investor · Georgia

Verified Google review

★★★★★

"I've used the $5k+ engineering firms before. This was the same quality report at a fraction of the price, and the team answered every question. Wish I'd found them sooner."

M. Brooks

Commercial owner · Ohio

Verified Google review

★★★★★

"As a short-term rental host, the bonus depreciation alone paid for years of cost seg studies. Clear report, fast turnaround, real humans behind it. Couldn't recommend more."

L. Carter

STR host · Tennessee

Verified Google review

"My CPA quoted me $6,500 for a cost segregation study. DIY Cost Seg did the same thing for a few hundred dollars — a real specialist reviewed and signed it, and it produced over $60,000 in first-year deductions. My accountant had zero issues. I won't do cost seg any other way now."

— Michael R., real estate investor · Verified Google review

The honest comparison

How DIY Cost Seg stacks up against the field

Bigger properties, a low flat starting price, the best reviews, and optional audit support in writing — here's how we compare on the things that matter.

← scroll the table to compare →

	DIY Cost Seg	Cost Seg EZ	Re Cost Seg	CSSI	Cost Seg Guys	Seneca
Instant self-service study	✓ Yes	✓ Yes	✕ 5–10 days	✕ No software	✕ 4–6 wks	✕ Quote only
Turnaround	Minutes	~15 min	5–10 days	Weeks	4–6 weeks	Weeks
Max property basis	Up to $5M	Under $1M	~$800K	Any	—	$450K floor
Starting price	$495	$595	$950+	Quote	$1,000+	~$7,000
Free instant estimate, no card	✓ Yes	—	✕	✕	✕	✕
U.S. team behind it	✓ Yes	Add-on	✓ Yes	✓ Yes	✓ Yes	✓ Yes
Audit support	✓ Add-on, in writing	—	—	—	—	—
All 50 states + international	✓ Yes	U.S.	U.S.	U.S.	U.S.	U.S.
Live phone support	✓ Yes	—	—	✓	—	—
Average review rating	5.0 ★	4.9 ★	4.8 ★	—	—	—
Studies completed	15,000+	~3,000	15,000+	Unknown	Thin	Claims 10,200+

Based on publicly available competitor information as of 2026; competitor figures may change — verify before relying on them. "—" = not publicly stated.

Built to IRS standards

The same authorities a $5,000–$15,000 engineered study cites

"Instant" refers to how fast you get it. Every study is built on the methodology and references the IRS expects to see.

✓
IRS Audit Technique GuideThe IRS's own framework for how a supportable cost seg study should be conducted.
✓
Rev. Proc. 87-56 asset classesProper recovery periods so every component is depreciated correctly.
✓
IRC §168(k) bonus depreciationCurrent-year rules applied to maximize your first-year deduction.
✓
RSMeans & Marshall & Swift cost dataEngineering-grade cost estimating — the industry-standard sources.

Who stands behind your report

Cost segregation team with 20+ years' experience

U.S.-based team

Issued under Cost Seg Specialists Inc.

Built on the IRS Audit Technique Guide methodology

Live phone support — reach a human

Downloadable sample report available

✓

The engine behind 15,000+ studies

Your study runs on the same engineered methodology our team has used across 15,000+ studies over 20+ years — the asset classifications, cost data, and depreciation rules the IRS Audit Technique Guide lays out. It's that process, tested under IRS audits, built into software.

IRS Audit Technique GuideRev. Proc. 87-5615,000+ studies

Common questions

Questions investors ask before they start

Is an instant cost seg study built in alignment with IRS standards? +

Yes. The "do-it-yourself" part is simply you providing the property information — not you performing the engineering analysis. Our engine applies the same methodology, cost data, and asset classifications a traditional study uses, and a U.S. specialist reviews and signs every report before it's issued under Cost Seg Specialists Inc.

What actually happens if I get audited? +

Audit support is available as an optional add-on, with the real terms published up front — the scope of support, who assists you, and refund conditions — so you know exactly what's covered before you add it.

Can I do a study on a property I bought years ago? +

Yes — you don't have to have bought it this year. A look-back study may help you catch up depreciation on a property placed in service in a prior year. Ask your CPA whether Form 3115 and catch-up depreciation apply to your situation.

Why is it so much cheaper than a traditional study? +

A traditional fully engineered study can run $5,000–$15,000. Our streamlined digital process automates much of the calculation and adds expert human review, with additional service levels available for properties requiring greater detail or an on-site inspection.

Who's behind the company? +

A named, U.S.-based team of cost segregation specialists with 20+ years in the industry. Reports are issued under Cost Seg Specialists Inc., and you can reach a real person by phone. We pioneered the original self-service cost seg software and are trusted by CPAs nationwide.

What size and type of properties qualify? +

Residential and commercial, short-term and long-term rentals, in all 50 states (including Alaska and Hawaii) and select international vacation rentals — on properties up to a $5M basis through the instant tool. Larger or more complex assets fit our Virtual or Fully Engineered tiers.

Do I have to pay before I see my savings? +

No. The calculator shows your estimated first-year deduction on screen, for free, before you ever enter a card. You decide whether the savings are worth it — most investors find the deduction is many times the cost of the study.

Cut Your Tax Bill by $30k–$700k+ This Year — in Minutes

Cost Segregation 101: Front-load your depreciation. Legally. In year one.

Without a study: 27.5 or 39 years

A study finds what qualifies for 5, 7, or 15 years

Bonus depreciation lets you take it all in year one

Large deductions now, not spread over decades

Cost segregation works for most real estate investors — if the property qualifies.

Short-term rental (STR) owners

Long-term rental investors

Commercial property owners

Real estate syndicates & funds

New construction & major renovations

Properties purchased in the last 3–5 years

Fully Engineered Study Results —Without the Hassle, the Markup, or the Wait.

✕ Hiring a Traditional Cost Seg Firm

✓ DIY Cost Seg

Properties under $3M were priced out of cost segregation. We built the methodology that changed that — and we built it first.

Cost segregation software built for real estate investors — and the CPAs who serve them.

Established methodology, professionally reviewed

Done in minutes, not weeks

Issued under Cost Seg Specialists Inc.

Three steps from property address to a filed study

Tell us about your investment property

See your savings instantly

Download your professionally reviewed study

An example study — and a sample report

Cost Segregation Study

Works for nearly every income property

An instant study, backed by 20 years of IRS-tested work

Instant — up to $5M

Optional audit support, in writing

An engineered methodology aligned with IRS standards

All 50 states + international

The best reviews in the category

Up to 90% less than an engineered study

One firm, three study options

Is cost segregation right for you?

We're the cost seg firm your CPA firm uses

How DIY Cost Seg stacks up against the field

Audit support, with the terms in writing.

The same authorities a $5,000–$15,000 engineered study cites

Offer cost seg to your clients — under your own brand

Questions investors ask before they start

See your first-year deduction in about a minute

Fully Engineered Study Results —
Without the Hassle, the Markup, or the Wait.