Concrete Calculator › Cost by city › Seattle, WA
Concrete Cost in Seattle, WA
Concrete for a 20×20 ft (400 sq ft) 4-inch concrete slab in Seattle, WA costs about $852 ($724–$980). Local 2026 price is around $172 per cuyd. Free calculator inside.
What goes into concrete cost in Seattle
The line items below are 2026 national averages adjusted by the WA construction-cost factor (×1.15). A written Seattle quote is usually built from these pieces — use them to sanity-check any bid line by line before you sign.
| Cost item | Typical Seattle price | Unit |
|---|---|---|
| Ready-mix concrete, 3,000–4,000 PSI | $172 – $213 | per cu yd delivered |
| Labor: forming, pouring & finishing | $4.6 – $9.2 | per sq ft |
| Gravel base & subgrade prep | $1.15 – $2.3 | per sq ft |
| Wire mesh / rebar reinforcement | $0.4 – $1.15 | per sq ft |
| Short-load fee (orders under ~4 cu yd) | $86 – $172 | per delivery |
| Residential flatwork permit | $57 – $345 | per project |
Permit fees are set by the city rather than the market — confirm current fees with the local building department.
What’s different about building in Seattle
Seattle has no meaningful frost line — code still requires footings to bear about 12 inches into undisturbed soil, but frost heave is not the design problem it is up north. Check specifics with Seattle Department of Construction & Inspections (SDCI).
Permits: for larger flatwork, driveways, or anything structural, check requirements with Seattle Department of Construction & Inspections (SDCI) before work starts.
Estimate your own Seattle project
Prices in Seattle, WA run about +15% versus the national average. Enter your dimensions — the calculator starts from the local $172 per cuyd rate; change it to your supplier's quote for an exact figure.
Material shopping list
- Order about 4.94 cubic yards of concrete.
- Budget about $852 before delivery, taxes, and labor.
- Add 5–10% waste for uneven subgrade, cuts, settling, or spillage.
Formula & assumptions
Area = length x width. Volume = area x depth / 12. Cubic yards = cubic feet / 27. Cost = quantity x local unit price.
- Default depth: 4 inches
- Default price: $172 per cuyd
- 80-lb bags yield: 0.6 cu ft each
These assumptions make the estimate easy for search engines and AI answer tools to verify. Replace the default price with your supplier quote for a local estimate.
Concrete cost in Seattle by project size
Material quantities use the local Seattle unit price; the last column adds delivery, base prep, and labor at WA-adjusted rates. Click any size for its full breakdown and calculator.
| Project size | You need | Material cost | Installed estimate |
|---|---|---|---|
| 10×10 ft · 4 in | 1.23 cu yd | $213 | $690 – $1,150 |
| 12×12 ft · 4 in | 1.78 cu yd | $307 | $994 – $1,656 |
| 12×16 ft · 4 in | 2.37 cu yd | $409 | $1,325 – $2,208 |
| 16×20 ft · 4 in | 3.95 cu yd | $681 | $2,208 – $3,680 |
| 20×20 ft · 4 in | 4.94 cu yd | $852 | $2,760 – $4,600 |
| 24×24 ft · 4 in | 7.11 cu yd | $1,227 | $3,974 – $6,624 |
| 30×40 ft · 4 in | 14.81 cu yd | $2,556 | $8,280 – $13,800 |
| 40×50 ft · 4 in | 24.69 cu yd | $4,259 | $13,800 – $23,000 |
Installed ranges assume straightforward access and a buildable subgrade; steep, tight, or poor-soil sites price above the top of the range.
Concrete questions Seattle homeowners ask
- How much does a concrete slab cost in Seattle?
- Materials alone for a 20×20 ft (400 sq ft) 4-inch concrete slab run about $852 in Seattle. Fully installed — gravel base, forms, reinforcement, labor, and finishing — most homeowners pay $2,760 to $4,600 for the same slab, roughly $6.9–$11.5 per square foot.
- What does ready-mix concrete cost per yard in Seattle?
- Plan on $172–$213 per cubic yard delivered for a standard 3,000–4,000 PSI mix in the Seattle area. Orders under about 4 cubic yards usually add a short-load fee of $86–$172, so small pours cost noticeably more per yard.
- Do I need a permit to pour a concrete slab in Seattle?
- Driveways, sidewalks, and anything structural almost always require one; small detached patio pads sometimes fall under the permit threshold. Confirm with Seattle Department of Construction & Inspections (SDCI) before you pour — a permit costs far less than being ordered to remove finished work.
- Is it cheaper to pour concrete myself in Seattle?
- Labor and finishing account for $4.6–$9.2 per square foot of the installed price, so DIY can roughly halve the cost of a simple pad. But concrete is unforgiving: once the truck arrives you have under two hours to place, screed, and finish. Most first-timers cap DIY at about 100–150 square feet.
- How thick should my slab be?
- Four inches is standard for patios and walkways; use 5–6 inches for driveways or anything carrying vehicles. Going from 4 to 6 inches adds 50% more concrete, so match the thickness to the real use.
- How can I save money on concrete in Seattle?
- Combine small pours into one delivery to clear the short-load threshold, handle your own excavation and gravel base, and collect at least three written Seattle quotes — 30% spreads between local bids are normal.
Concrete cost in nearby cities
Regional estimate = national average adjusted by a WA cost factor. Not a quote. Actual prices vary by site conditions, access, and supplier.