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Cheapest States for ADU / Guest House (2026)

ADU / Guest House cost ranked across all 50 states for a typical 500 sq ft project. The Southeast is cheapest (from $70,000); the West is priciest (up to $260,000) — a spread of about 50%.

Reviewed by , Founder & Cost Analyst, BuildCost

Last updated

Quick Answer

Which states are cheapest for an adu / guest house? ADU / Guest House is least expensive in the Southeast — including Alabama, Arkansas, Florida, Georgia, and Kentucky — where a typical 500 sq ft project averages $110,000. It is most expensive in the West (Alaska, California, Colorado, Hawaii, and Idaho), averaging $165,000. The national average is about $131,500 in 2026.

Cheapest region
Southeast
Priciest region
West
National average
$131,500
State spread
~50%
Cheapest — Southeast
$70,000$170,000

$140$340 per sq ft. States include Alabama, Arkansas, Florida, Georgia, and Kentucky.

Most expensive — West
$105,000$260,000

$210$520 per sq ft. States include Alaska, California, Colorado, Hawaii, and Idaho.

ADU / Guest House Cost by Region, Ranked

Cheapest to most expensive, for a typical 500 sq ft project (2026).

RankRegionPer sq ftTypical total
1Southeast$140$340$70,000$170,000
2Midwest$150$360$75,000$180,000
3Southwest$160$390$80,000$195,000
4Northeast$180$420$90,000$210,000
5West$210$520$105,000$260,000

ADU / Guest House Cost by State, Ranked (2026)

All 50 states, cheapest to most expensive, for a typical 500 sq ft project. Click any state for a full local breakdown.

#StateRegionAvg totalvs. US avg
1AlabamaSoutheast$110,000-16%
2ArkansasSoutheast$110,000-16%
3FloridaSoutheast$110,000-16%
4GeorgiaSoutheast$110,000-16%
5KentuckySoutheast$110,000-16%
6LouisianaSoutheast$110,000-16%
7MississippiSoutheast$110,000-16%
8North CarolinaSoutheast$110,000-16%
9South CarolinaSoutheast$110,000-16%
10TennesseeSoutheast$110,000-16%
11VirginiaSoutheast$110,000-16%
12West VirginiaSoutheast$110,000-16%
13IllinoisMidwest$117,500-11%
14IndianaMidwest$117,500-11%
15IowaMidwest$117,500-11%
16KansasMidwest$117,500-11%
17MichiganMidwest$117,500-11%
18MinnesotaMidwest$117,500-11%
19MissouriMidwest$117,500-11%
20NebraskaMidwest$117,500-11%
21North DakotaMidwest$117,500-11%
22OhioMidwest$117,500-11%
23South DakotaMidwest$117,500-11%
24WisconsinMidwest$117,500-11%
25ArizonaSouthwest$125,000-5%
26New MexicoSouthwest$125,000-5%
27OklahomaSouthwest$125,000-5%
28TexasSouthwest$125,000-5%
29ConnecticutNortheast$140,000+6%
30DelawareNortheast$140,000+6%
31MaineNortheast$140,000+6%
32MarylandNortheast$140,000+6%
33MassachusettsNortheast$140,000+6%
34New HampshireNortheast$140,000+6%
35New JerseyNortheast$140,000+6%
36New YorkNortheast$140,000+6%
37PennsylvaniaNortheast$140,000+6%
38Rhode IslandNortheast$140,000+6%
39VermontNortheast$140,000+6%
40AlaskaWest$165,000+25%
41CaliforniaWest$165,000+25%
42ColoradoWest$165,000+25%
43HawaiiWest$165,000+25%
44IdahoWest$165,000+25%
45MontanaWest$165,000+25%
46NevadaWest$165,000+25%
47OregonWest$165,000+25%
48UtahWest$165,000+25%
49WashingtonWest$165,000+25%
50WyomingWest$165,000+25%

"Avg total" is the mid-range estimate for a 500 sq ft project. "vs. US avg" compares it against the $131,500 national average.

How this ranking is calculated

BuildCost models adu / guest house pricing across five U.S. regions (Northeast, Southeast, Midwest, Southwest, West). Each state is ranked by its region's labor and material costs, so states in the same region share a baseline — actual prices still vary by metro, contractor, and site conditions. Totals assume a typical 500 sq ft project at mid-grade materials. For a precise local figure, open your state's page or run the free estimate tool.

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Frequently Asked Questions

What is the cheapest state for an adu / guest house?

The lowest adu / guest house costs are in the Southeast region — states like Alabama, Arkansas, Florida, Georgia, and Kentucky. A typical 500 sq ft project there runs $70,000–$170,000, averaging $110,000 in 2026.

What is the most expensive state for an adu / guest house?

The highest adu / guest house costs are in the West region — states like Alaska, California, Colorado, Hawaii, and Idaho. A typical 500 sq ft project there runs $105,000–$260,000, averaging $165,000 — roughly 50% more than the cheapest region.

How much does an adu / guest house cost on average in the US?

Nationally, an adu / guest house costs $84,000–$203,000 for a typical 500 sq ft project, averaging about $131,500 in 2026.

Why does adu / guest house cost vary by state?

The biggest driver is regional labor rates, which can differ 30–50% between markets. Material logistics, permit fees, code requirements, climate-driven construction needs, and local contractor demand also push costs up or down. BuildCost models pricing across five U.S. regions, so states in the same region share a baseline.

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How big is your ADU / Guest House?

A studio ADU is ~300 sq ft. A 1-bed ADU is ~500 sq ft. A 2-bed ADU is ~700–900 sq ft.

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ADU / Guest House cost guide

National averages, labor vs. materials, hidden costs, and contractor questions.

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