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Reno ADU Cost Calculators
Six calculators built on the 2026 figures published on this site. Enter your lot, your elevation, your utility distances and your specification, and see a realistic range with every line broken out — no email, no sign-up, no waiting for a callback.
Choose your calculator
The whole project budget — build, permits, utilities and the cost of the money.
Open the calculatorDetached ADU Cost CalculatorA separate building, by size, finish, elevation, ground and trench distance.
Open the calculatorAttached ADU Cost CalculatorAn addition sharing a wall, by how it ties in and what systems it shares.
Open the calculatorGarage Conversion Cost CalculatorConverting a garage, by slab condition, panel capacity and utility distance.
Open the calculatorADU Remodeling Cost CalculatorRenovating an existing unit, by scope, age and systems replaced.
Open the calculatorADU Design Cost CalculatorDrawings, engineering, survey and permit fees, as a share of your build.
Open the calculatorThe two things most people get wrong
The lot costs more than the building
People budget an ADU by pricing the unit — square feet times a rate they read somewhere. The number that actually decides the project is the lot it lands on. Washoe County sets the design ground snow load by elevation and it runs from 43 psf on the valley floor to 203 psf at 6,000 feet, which is a different roof rather than a percentage. Frost depth is 24 inches and the region is Seismic Design Category D2, so footings go deeper and are tied together more. And every foot between the house and the unit is trench carrying sewer, water, gas and power. The same drawing genuinely costs different money in Sparks and in Galena.
The build price is not the project price
A construction contract prices a building. It does not usually price a service upgrade when the panel cannot carry a second dwelling, the off-street parking space the ordinance requires, separate meters, putting the yard back after the trench, appliances and window coverings, furniture, or the interest on borrowed money across a build that runs months. Those lines are what turn a budget that looked fine into a project that ran out at ninety percent. The construction calculator keeps them visible and separate.
How to use these numbers
Typical ranges in Reno
| Calculator | Typical range |
|---|---|
| ADU Construction Cost Calculator | $60,000 – $450,000+ |
| Detached ADU Cost Calculator | $120,000 – $450,000+ |
| Attached ADU Cost Calculator | $100,000 – $380,000+ |
| Garage Conversion Cost Calculator | $60,000 – $175,000+ |
| ADU Remodeling Cost Calculator | $12,000 – $150,000+ |
| ADU Design Cost Calculator | $6,000 – $60,000+ |
These span the realistic low and high ends across all sizes, elevations and site conditions. Your project sits at a specific point inside its range — the calculators tell you where.
Or price the whole project
These are the per-project figures published on this site, for when you want to sanity-check the total rather than build it up from the pieces.
| ADU project | Typical cost range |
|---|---|
| Garage conversion ADU | $60,000 – $130,000 |
| Small detached ADU (under 500 sq ft) | $120,000 – $220,000 |
| One-bedroom detached ADU (500 – 750 sq ft) | $180,000 – $320,000 |
| Larger detached ADU (750+ sq ft) | $250,000 – $450,000+ |
| Attached ADU | $150,000 – $300,000 |
| ADU remodeling & renovation | $30,000 – $150,000 |
| Higher-end custom ADU | $400,000+ |
Design snow load by elevation
Washoe County design criteria, ground snow load, Risk Category II, west of US 395. This single table explains more ADU price variation in this region than any other factor, and it is why every calculator here asks your elevation.
| Elevation | Ground snow load | Typical areas |
|---|---|---|
| 4,500 – 5,000 ft | 43 psf | Reno valley floor, Sparks, Spanish Springs, Sun Valley |
| 5,100 ft | 59 psf | Lower foothills |
| 5,200 ft | 75 psf | — |
| 5,300 ft | 92 psf | Upper foothills |
| 6,000 ft | 203 psf | Galena, Montreux, St James Village |
| 7,000 ft | 286 psf | Virginia City Highlands and above |
| 8,000 ft | 328 psf | — |
Alongside a 24-inch frost depth, Seismic Design Category D2, a 120 mph design wind speed and a 17°F winter design temperature. Confirm the criteria for your specific parcel with Washoe County before designing to them.
What the law now allows
Nevada AB 396, effective 1 July 2026
Approved 6 June 2025. Its ADU provisions apply to counties over 100,000 — Washoe County, unincorporated areas included — and cities over 60,000, which covers Reno and Sparks. From that date a local ordinance may not ban a separate kitchen, require more than one parking space, impose side or rear setbacks stricter than those applying to the primary residence, or prohibit long-term rental. It sets no statewide size cap and no fee limits, and it does not address owner-occupancy.
City of Reno ordinance, adopted 8 October 2025
What we can state with confidence: a minimum lot size of 5,000 square feet, at least one off-street parking space, and a requirement that the ADU be both smaller and shorter than the main house. Other figures are widely cited — 50 percent of the primary dwelling up to 1,200 square feet, a height limit near 16 feet, 5-foot side and rear setbacks — but should be treated as unconfirmed and checked against the current ordinance before you design to them.
Two exclusions that catch people
Properties inside the Tahoe Regional Planning Agency area — which includes Incline Village — are outside AB 396, and TRPA runs its own review with land coverage and scenic requirements that have no valley-floor equivalent. Separately, private HOA covenants are untouched by the law and can still prohibit an ADU outright. Read your CC&Rs before spending money on design, particularly in the master-planned communities around Reno.
City or county? It decides everything
Reno and Sparks are cities with their own building departments and fee schedules. Spanish Springs, Sun Valley, Lemmon Valley, Golden Valley, Cold Springs and much of the outlying area are unincorporated Washoe County. Plenty of addresses that say Reno in the mail are county parcels. Confirm which one covers yours before anyone quotes you a permit fee or a timeline — independent sources put ADU permitting at roughly three to six months either way.
What these calculators are — and what they are not
Built on published 2026 figures
The per-project ranges published on our own service pages, corroborated against independent 2026 northern Nevada ADU data, plus Washoe County design criteria and the current Nevada and Reno rules. Where our own pages and an outside guide disagree, our pages win — a calculator that contradicts the page next to it is worse than no calculator. The one exception is design, where this site publishes no figures at all; that calculator says so and names the outside sources it uses instead.
Honest about uncertainty
Every result is a range, and contingency is shown as its own line rather than hidden in the total. When a configuration lands outside the band published on this site, the calculator says so and explains why rather than quietly printing a different number. The widest uncertainty is always the ground, because nobody knows what is under it until someone digs.
Not a contractor quote
No calculator can see your soil, your slope, how far your utility connections actually run, or what your lot and your HOA will allow. Those decide real prices. Treat every number here as a planning figure and get someone to stand on the lot before you commit.
Ready for a real number?
We design and build ADUs across Reno, Sparks, Spanish Springs and Washoe County. Every project starts with a free, no-pressure visit, so you can see what your property actually allows — and what it costs — before committing to anything.
Get my free consultationFrequently asked questions
How accurate are these ADU calculators?
They are built from the 2026 cost figures published on this site's own service pages, corroborated against independent 2026 northern Nevada ADU data, and checked against Washoe County's design criteria, Reno's October 2025 ADU ordinance and Nevada's AB 396. They are accurate enough to plan and budget around. They are not accurate enough to sign a contract against, because no calculator can see your soil, your slope, how far your utilities actually run, or what your lot and your HOA will allow.
Why do two ADUs the same size cost so differently?
Because size is only one of four drivers, and on this side of the Sierra it is not the biggest. Elevation sets the design snow load, which runs from 43 psf on the valley floor to 203 psf at 6,000 feet — a different roof, not a surcharge. Ground decides whether you are pouring a slab or engineering retaining and drainage. Distance decides how much trench carries sewer, water, gas and power. And specification does the rest. Two 600 square foot units can legitimately be $150,000 apart.
What does an ADU cost in Reno?
The figures published on this site put a garage conversion at $60,000 to $130,000, a small detached unit under 500 square feet at $120,000 to $220,000, a one-bedroom detached of 500 to 750 square feet at $180,000 to $320,000, a larger detached unit at $250,000 to $450,000 and beyond, an attached ADU at $150,000 to $300,000, renovation of an existing unit at $30,000 to $150,000, and a higher-end custom ADU at $400,000 and up. The calculators here let you build a number up from your own lot rather than picking a row from a table.
What does Nevada's AB 396 actually do?
AB 396 was approved on 6 June 2025 and its ADU provisions take effect on 1 July 2026. It covers counties over 100,000 — Washoe included, unincorporated areas as well — and cities over 60,000, which covers Reno and Sparks. From that date a local ordinance may not ban a separate kitchen, require more than one parking space, impose side or rear setbacks stricter than those applying to the primary residence, or prohibit long-term rental. It sets no statewide size cap and no fee limits. Two exclusions matter: properties in the Tahoe Regional Planning Agency area, which includes Incline Village, and private HOA covenants, which are untouched and can still block an ADU outright. Confirm the current position before relying on any of it.
What does Reno's own ordinance require?
Reno adopted its ADU ordinance on 8 October 2025. The requirements we can state with confidence are a minimum lot size of 5,000 square feet, at least one off-street parking space, and that the ADU be both smaller and shorter than the main house. Other figures are widely cited — 50 percent of the primary dwelling up to 1,200 square feet, a height limit around 16 feet, 5-foot side and rear setbacks — but should be treated as unconfirmed and checked against the current ordinance. Note also that many addresses with a Reno mailing address are in unincorporated Washoe County, which is a different department and a different rule set.
Do I have to give you my details to see a price?
No. Every calculator on this site works without an email address, a phone number or a sign-up. Use them, note the number, and contact us only if you want a real quote.