How Our Cost Estimates Work
Each Kolmo calculator builds an itemized planning estimate from the inputs you enter. Materials and labor are priced line by line. Where the scope calls for them, the estimate adds lines such as a permit fee, a contingency or a job minimum. The result is a range, not a quote. This page shows what goes into the number, what stays out, and how the prices were set.
What Goes Into Your Estimate
Labor, Priced per Task
Each task is its own line item, with its quantity, unit and rate on the line. Interior painting and deck lines bill hours at the task's hourly rate. Other lines bill per square foot, per foot or per item. No single hourly rate applies across trades.
Materials, Line by Line
Material lines price the quantity your inputs call for, such as gallons of paint, at the unit price in Kolmo's material catalog. Change a material and its line changes with it.
Permits: Seattle's Own Fee Schedule
Six calculators carry a permit line. Five of them (kitchen, bathroom, basement, deck and ADA) price the building permit from Seattle's own 2026 SDCI fee schedule on the job's value, the figure Kolmo's permit engine gives; the ADU calculator carries a flat permits-and-fees allowance by type. No calculator takes your location as a pricing input, so every job is priced for Seattle. The lines are listed below. For fees in another city, use the permit lookup.
Overhead and Profit: Kitchen Only
The kitchen calculator adds one overhead-and-profit line at 20% of direct cost plus general conditions. Permits stay out of that base. No other calculator carries a separate overhead line.
Contingency: Basement and ADU
The basement calculator includes a 5% contingency, plus 8 points on a home built before 1978. The ADU calculator includes 8%, plus 10 points before 1978 for attached ADUs and basement or garage conversions. Both totals already carry it, so do not add another. For the other calculators, hold 10-15% on a typical scope and about 20% on a pre-1978 home, where asbestos, lead paint or knob-and-tube wiring may surface.
Job Minimums
A small job still costs the truck, the crew's trip, and setup and teardown, and no one builds a bathroom or a kitchen for what its size alone would price at. When a calculated total falls below the job minimum, the difference is added as its own line, so the line items still add up to the total. The minimums are listed below.
How the Calculator Builds Your Number
- 1
Pick a project type and enter what that calculator asks for: sizes, materials, scope and options. No calculator takes your location as a pricing input.
- 2
Material lines multiply the quantity your inputs call for by the unit price in Kolmo’s material catalog.
- 3
Labor lines price each task on its own line, with its quantity, unit and rate.
- 4
Scope lines are added where a calculator uses them: a permit line (Seattle’s fee schedule, or a flat allowance on the ADU), overhead and profit (kitchen), design and permit-set drawings (ADU), and a contingency (basement and ADU).
- 5
The lines add up to a point total. A total below its job minimum is raised to it on a line of its own: on the trade calculators the total is raised, and on the kitchen, bathroom, basement, new-deck and ADU calculators the total is raised until the range’s low end reaches the kind of job’s starting price.
- 6
The point total is shown as a range, as described under How Ranges Work.
Permit Lines by Calculator
- Kitchen
- None for a cosmetic refresh. A standard remodel or full gut carries Seattle's building permit, priced from the 2026 SDCI fee schedule on the job's value, field-inspection path: $1,561 on a 160 sq ft standard remodel.
- Bathroom
- None for a cosmetic update. A standard remodel or full gut carries Seattle's building permit, priced from the 2026 SDCI fee schedule on the job's value, field-inspection path: $802 on a 40 sq ft standard remodel.
- Basement
- Seattle's building permit, priced from the 2026 SDCI fee schedule on the job's value, full plan review: $1,462 on an 800 sq ft standard finish.
- ADU
- $7,500 for a detached ADU. $4,800 for an attached ADU. $2,200 for a basement conversion. $3,200 for a garage conversion.
- Deck
- New decks more than 18 inches above grade only: Seattle's building permit, priced from the 2026 SDCI fee schedule on the deck's value, on the field-inspection path ($769 on a 16x20 Trex Enhance deck 3 ft up), or full plan review for a deck more than 8 ft above grade. None for work on an existing deck.
- ADA accessibility
- Seattle's building permit, priced from the 2026 SDCI fee schedule on the job's value, full plan review, when a structural item is selected (walk-in shower, wider doorways, ramp or roll-under sink): $850 on a walk-in shower conversion. A stair lift adds its own $250 permit line.
Interior painting, exterior painting, flooring, windows, siding, fence and landscaping carry no permit line. The ADU line is an allowance set by type; the others follow Seattle's fee schedule. For permit requirements and fees at a specific address, use the Seattle-area permit lookup.
Job Minimums
Kitchen, bathroom, basement, new-deck and ADU estimates start at a set price for each kind of job: the low end of the range shown never sits under it, and a smaller job is topped up to it on a “Job minimum” line.
- Powder room$3,200
- Bathroom refresh$4,000
- New tub or shower, same layout$6,250
- Full bathroom$13,800
- Kitchen refresh$9,250
- Full kitchen, new cabinets$21,000
- Kitchen with a layout change$26,750
- High-end kitchen, custom cabinets$50,000
- New deck$5,000
- Basement room$9,500
- Basement with a full bathroom$23,300
- Basement suite, kitchenette and full bathroom$65,000
- ADU, any kind$65,000
On the trade calculators, a total below the minimum is raised to it on a “Mobilization & Job Minimum” line. The plumbing, garage door and door replacement calculators have no minimum.
- Interior painting$380
- Exterior painting$1,800
- Siding$1,800
- Windows$605
- Deck, on the deck you have$475
- Fence$1,425
- Flooring$710
- Landscaping$475
- ADA accessibility$1,500
- Electrical$260
- Concrete$1,500
- Insulation$475
- Gutters$855
What Is Not Included
- Hazardous material abatement, such as asbestos-cement siding or lead paint. It is separately licensed work.
- Structural repair discovered after demolition.
- Utility upgrades, such as a new electrical panel, unless you price one in the electrical calculator.
- Design fees and financing costs. The ADU calculator is the one exception on design: it includes design and permit-set drawings.
How Ranges Work
Every calculator shows its estimate as a range, from 15% below to 15% above the point total. The basement and ADU calculators also compute their own range in the engine and show it with the result: 12% below to 18% above for a basement, and 15% below to 20% above for an ADU. Estimates requested through Kolmo's API return the 15% range, or the engine's own range for basement and ADU.
The range is 15% below to 15% above the point total. Site conditions, finish selections and permits move the number inside that band. Quote the range, not just the point figure.
The range and a contingency are different things. The range is how firm the figure is. A contingency is money held back for what demolition uncovers.
How Prices Are Set
These are Kolmo’s own prices.
Our Estimation Process
From Inputs to Line Items
Each calculator turns your inputs into line items. Every line shows a quantity, a unit, a unit cost and a total, and the lines add up to the estimate.
How to Get a Firm Number
A calculator figure is a planning range for Seattle-area work, not a quote. For a firm price, contact Kolmo with your project details and the calculator inputs you used.
Request a quoteTry It on Your Project
Pick the calculator closest to your project. Each one asks for the inputs its scope needs and returns itemized line items and a range.
The garage conversion page is a cost guide, not a calculator. To price a garage converted into a legal unit, use the ADU calculator and choose its garage-conversion type.