What an accessory dwelling unit actually costs to build in 125 cities across 26 states — total build, per square foot, garage conversion and prefab. Costs move with local labour, permit fees and lot access, so a national average is close to useless.
| City | Build cost | Per sq ft |
|---|---|---|
| Mobile, AL | $90,000-$175,000 | $120-$195 |
| Birmingham, AL | $90,000-$180,000 | $120-$200 |
| Huntsville, AL | $95,000-$185,000 | $125-$200 |
| Detroit, MI | $90,000-$200,000 | $140-$240 |
| Grand Rapids, MI | $90,000-$200,000 | $150-$250 |
| City | Build cost | Per sq ft |
|---|---|---|
| Paradise Valley, AZ | $300,000-$600,000 | $350-$750 |
| Woodinville, WA | $325,000-$550,000 | $400-$650 |
| Seattle, WA | $325,000-$550,000 | $400-$650 |
| Sammamish, WA | $325,000-$550,000 | $400-$650 |
| Redmond, WA | $325,000-$550,000 | $400-$650 |
These are build ranges, not quotes. The figure that moves most between cities is not materials — it is labour, permit fees and how easily a crew can get equipment into your back garden. A narrow side return can cost more than a kitchen.
$150,000-$280,000 to build · $175-$350 per sq ft
See the Avondale cost breakdown →$150,000-$280,000 to build · $175-$350 per sq ft
See the Buckeye cost breakdown →$125,000-$250,000 to build · $140-$280 per sq ft
See the Chandler cost breakdown →$150,000-$280,000 to build · $175-$350 per sq ft
See the Gilbert cost breakdown →$150,000-$280,000 to build · $175-$350 per sq ft
See the Glendale cost breakdown →$150,000-$280,000 to build · $175-$350 per sq ft
See the Goodyear cost breakdown →$150,000-$280,000 to build · $175-$350 per sq ft
See the Mesa cost breakdown →$300,000-$600,000 to build · $350-$750 per sq ft
See the Paradise Valley cost breakdown →$150,000-$280,000 to build · $175-$350 per sq ft
See the Peoria cost breakdown →$150,000-$280,000 to build · $200-$350 per sq ft
See the Phoenix cost breakdown →$160,000-$320,000 to build · $200-$400 per sq ft
See the Scottsdale cost breakdown →$150,000-$280,000 to build · $175-$350 per sq ft
See the Surprise cost breakdown →$150,000-$280,000 to build · $175-$350 per sq ft
See the Tempe cost breakdown →$150,000-$250,000 to build · $150-$300 per sq ft
See the Tucson cost breakdown →$220,000-$450,000 to build · $300-$500 per sq ft
See the Anaheim cost breakdown →$250,000-$500,000 to build · $400-$700 per sq ft
See the Berkeley cost breakdown →$220,000-$400,000 to build · $300-$550 per sq ft
See the Burbank cost breakdown →$300,000-$450,000 to build · $375-$600 per sq ft
See the Carlsbad cost breakdown →$300,000-$450,000 to build · $375-$600 per sq ft
See the Chula Vista cost breakdown →$170,000-$400,000 to build · $250-$500 per sq ft
See the Citrus Heights cost breakdown →$180,000-$320,000 to build · $180-$300 per sq ft
See the Corona cost breakdown →$300,000-$450,000 to build · $375-$600 per sq ft
See the El Cajon cost breakdown →$170,000-$400,000 to build · $250-$500 per sq ft
See the Elk Grove cost breakdown →$300,000-$450,000 to build · $375-$600 per sq ft
See the Escondido cost breakdown →$170,000-$400,000 to build · $250-$500 per sq ft
See the Folsom cost breakdown →$175,000-$320,000 to build · $180-$300 per sq ft
See the Fontana cost breakdown →$250,000-$460,000 to build · $300-$480 per sq ft
See the Fremont cost breakdown →$150,000-$320,000 to build · $200-$330 per sq ft
See the Fresno cost breakdown →$175,000-$375,000 to build · $275-$475 per sq ft
See the Glendale cost breakdown →$200,000-$425,000 to build · $300-$475 per sq ft
See the Hayward cost breakdown →$185,000-$420,000 to build · $300-$525 per sq ft
See the Huntington Beach cost breakdown →$185,000-$420,000 to build · $300-$525 per sq ft
See the Irvine cost breakdown →$215,000-$400,000 to build · $310-$450 per sq ft
See the Long Beach cost breakdown →$220,000-$400,000 to build · $300-$500 per sq ft
See the Los Angeles cost breakdown →$210,000-$400,000 to build · $250-$500 per sq ft
See the Oakland cost breakdown →$300,000-$450,000 to build · $375-$600 per sq ft
See the Oceanside cost breakdown →$180,000-$320,000 to build · $180-$300 per sq ft
See the Ontario cost breakdown →$150,000-$400,000 to build · $300-$450 per sq ft
See the Pasadena cost breakdown →$170,000-$400,000 to build · $250-$500 per sq ft
See the Rancho Cordova cost breakdown →$175,000-$350,000 to build · $250-$350 per sq ft
See the Rancho Cucamonga cost breakdown →$180,000-$320,000 to build · $180-$280 per sq ft
See the Riverside cost breakdown →$170,000-$400,000 to build · $250-$500 per sq ft
See the Roseville cost breakdown →$170,000-$400,000 to build · $250-$500 per sq ft
See the Sacramento cost breakdown →$150,000-$300,000 to build · $180-$280 per sq ft
See the San Bernardino cost breakdown →$250,000-$450,000 to build · $375-$600 per sq ft
See the San Diego cost breakdown →$300,000-$550,000 to build · $350-$650 per sq ft
See the San Francisco cost breakdown →$200,000-$450,000 to build · $300-$500 per sq ft
See the San Jose cost breakdown →$300,000-$480,000 to build · $450-$600 per sq ft
See the San Mateo cost breakdown →$180,000-$400,000 to build · $300-$500 per sq ft
See the Santa Ana cost breakdown →$250,000-$500,000 to build · $325-$550 per sq ft
See the Santa Monica cost breakdown →$200,000-$380,000 to build · $250-$400 per sq ft
See the Torrance cost breakdown →$175,000-$350,000 to build · $180-$350 per sq ft
See the Upland cost breakdown →$150,000-$300,000 to build · $150-$360 per sq ft
See the Jacksonville cost breakdown →$150,000-$320,000 to build · $250-$450 per sq ft
See the Miami cost breakdown →$150,000-$260,000 to build · $200-$260 per sq ft
See the Orlando cost breakdown →$100,000-$250,000 to build · $170-$350 site-built per sq ft
See the Tampa cost breakdown →$75,000-$350,000 to build · $150-$400 per sq ft
See the Boston cost breakdown →$220,000-$400,000 to build · $275-$450 per sq ft
See the Cambridge cost breakdown →$220,000-$400,000 to build · $275-$450 per sq ft
See the Medford cost breakdown →$250,000-$450,000 to build · $275-$450 per sq ft
See the Newton cost breakdown →$220,000-$400,000 to build · $275-$450 per sq ft
See the Quincy cost breakdown →$220,000-$400,000 to build · $275-$450 per sq ft
See the Somerville cost breakdown →$200,000-$400,000 to build · $275-$450 per sq ft
See the Waltham cost breakdown →$220,000-$360,000 to build · $275-$450 per sq ft
See the Worcester cost breakdown →$110,000-$260,000 to build · $180-$330 per sq ft
See the Henderson cost breakdown →$110,000-$230,000 to build · $180-$330 per sq ft
See the Las Vegas cost breakdown →$100,000-$220,000 to build · $180-$330 per sq ft
See the North Las Vegas cost breakdown →$200,000-$400,000 to build · $250-$450 per sq ft
See the Jersey City cost breakdown →$200,000-$400,000 to build · $250-$450 per sq ft
See the Montclair cost breakdown →$200,000-$375,000 to build · $275-$450 per sq ft
See the Princeton cost breakdown →$160,000-$300,000 to build · $200-$375 per sq ft
See the Trenton cost breakdown →$165,000-$300,000 to build · $200-$420 per sq ft
See the Beaverton cost breakdown →$225,000-$350,000 to build · $280-$440 per sq ft
See the Bend cost breakdown →$110,000-$285,000 to build · $150-$300 per sq ft
See the Eugene cost breakdown →$180,000-$280,000 to build · $250-$400 per sq ft
See the Portland cost breakdown →$170,000-$330,000 to build · $175-$275 per sq ft
See the Salem cost breakdown →$150,000-$350,000 to build · $250-$450 per sq ft
See the Austin cost breakdown →$130,000-$320,000 to build · $250-$400 per sq ft
See the Dallas cost breakdown →$130,000-$320,000 to build · $250-$400 per sq ft
See the Fort Worth cost breakdown →$140,000-$350,000 to build · $250-$400 per sq ft
See the Frisco cost breakdown →$140,000-$260,000 to build · $225-$350 per sq ft
See the Houston cost breakdown →$140,000-$350,000 to build · $250-$400 per sq ft
See the Plano cost breakdown →$140,000-$350,000 to build · $250-$400 per sq ft
See the Richardson cost breakdown →$125,000-$320,000 to build · $225-$400 per sq ft
See the San Antonio cost breakdown →$325,000-$550,000 to build · $400-$650 per sq ft
See the Bellevue cost breakdown →$325,000-$550,000 to build · $400-$650 per sq ft
See the Bothell cost breakdown →$325,000-$550,000 to build · $400-$650 per sq ft
See the Kirkland cost breakdown →$325,000-$550,000 to build · $400-$650 per sq ft
See the Redmond cost breakdown →$325,000-$550,000 to build · $400-$650 per sq ft
See the Sammamish cost breakdown →$325,000-$550,000 to build · $400-$650 per sq ft
See the Seattle cost breakdown →$130,000-$260,000 to build · $200-$400 per sq ft
See the Spokane cost breakdown →$150,000-$350,000 to build · $300-$520 per sq ft
See the Tacoma cost breakdown →$150,000-$350,000 to build · $200-$400 per sq ft
See the Vancouver cost breakdown →$325,000-$550,000 to build · $400-$650 per sq ft
See the Woodinville cost breakdown →