A two-step planning tool. Step 1 sizes your home from the rooms you select. Step 2 prices it across the three components of construction cost. Combined, you get a planning-level budget before any drawings are produced.
Select the rooms you need. Adjust dimensions if your version is bigger or smaller. The total adds 20% on top of the room subtotal for circulation, and includes the garage at full square footage.
| Room | W ft | L ft | Area SF |
|---|
Pick a level of design ambition. We'll combine it with your square footage from Step 1 to give you a planning-level budget for construction.
Construction Cost = Size × Design Ambition
Synced from Step 1 · or override here
Default room sizes are typical for modern custom homes in the Seattle–Bellevue area. Circulation (hallways, landings, transitions between rooms) runs about 20% on top of the room subtotal. The garage is included at full square footage.
Construction cost is the full amount you'll pay your contractor — net build, GC fee, and Washington sales tax. The GC fee typically runs 12–20% of net construction; we use 16% as a market midpoint. Sales tax in the Eastside area runs 10.0–10.5%; we use 10.1%. Design fees and permits are additional, typically 12–15% on top.
The number you land on is a planning-level estimate. Real costs vary with site conditions, design ambition, and market. Use this as a starting point for the conversation with your architect or builder, not as a bid.
Want the full picture, including design fees, the workplan, and how we work? We put together a Residential Guide that walks you through the whole process from first conversation to handing over the keys.
Get the Residential Guide →We wrote a five-part walk-through of what custom homes cost — from the components, to why "cost per square foot" can be misleading, to setting a real budget before you start designing.
Start with Part 1 →