How the app puts a price on a job it has never seen.

The homeowner picks the project type: kitchen, bathroom, basement, flooring, roofing, tub and shower, or a whole home. Then the square footage. Most line items scale with it. Cabinets, tile and flooring are priced per square foot or per linear foot; a toilet, a range or a permit costs the same in a 100 square foot bathroom as a 150 square foot one, and the tables know which is which.

The features add or change lines. An island adds an island countertop and island cabinets. A double vanity doubles the vanity, the sink, the faucet and the countertop. A second bathroom in a basement adds the plumbing rough in for it. An egress window is its own line with its own materials and labor. What the homeowner does not want is simply not on the list.

Each project type has three pricing tables: Basic, Modern and Luxury. The same job is priced three ways, and every line carries a material cost and a labor cost. In a kitchen the Basic table has stock cabinets and laminate counters; Modern has semi custom soft close cabinets and quartz; Luxury has custom cabinetry, premium stone and a pro style range. The homeowner sees all three and picks the one she is really thinking about.

A 200 square foot kitchen with an island at the national average, Modern tier, comes to $60,619: $29,613 in materials and $25,495 in labor across 32 lines, grouped like this:

• Cabinetry: $20,368 across 5 lines
• Appliances: $6,643 across 5 lines
• Countertops: $6,511 across 3 lines
• Flooring: $5,213 across 3 lines
• Preparation: $4,694 across 3 lines
• Electrical: $3,648 across 3 lines
• Finishing: $2,662 across 3 lines
• Plumbing: $2,102 across 2 lines
• Fixtures: $1,767 across 3 lines
• Administrative: $1,500 across 2 lines

On top of materials and labor the app adds a contingency, the way a real quote does: 10 percent on a kitchen, 8 percent on flooring, up to 12 percent on a whole home remodel or a basement, where the surprises live. It is shown as its own line, not hidden in the rates, so the homeowner sees what it is for.

Labor and materials do not cost the same in San Francisco and in Memphis. The app carries a cost multiplier for ZIP prefixes across the country and applies it to every line. A few of them:

• San Francisco (941xx): 1.60x
• Manhattan (100xx): 1.50x
• Boston (021xx): 1.45x
• Seattle (980xx): 1.38x
• Denver (800xx): 1.25x
• Atlanta (300xx): 1.00x
• Dallas (750xx): 1.00x
• St. Louis (630xx): 0.90x
• Memphis (380xx): 0.82x

A ZIP the app does not know is priced at 1.00, the national average.

Last, and most important: the number the homeowner sees is yours. On setup you pick 20 percent below the regional average, average, 20 percent above, 40 percent above, or type your own multiplier. Every price on your link is scaled to it, so the figure that keeps a homeowner off your driveway is the figure you would really have sent. That is what makes the third question, does this fit your budget, worth asking.

You set the floor for the work you take. When the Basic price of a job is under it, the homeowner still sees her price, and the app tells her plainly that the job is under what you take on. She never reaches your phone, and you never drive to her.

It is not your quote, and it says so on every price. It does not measure the room, walk the site, or know that the subfloor is rotten. It gives the homeowner a number that is close enough to be honest, built the way you would build one, before anyone has spent a drive on it. Then you do the estimate, for the ones worth doing.