What joist spacing should I use?

16 inch centers suit most decking, while some composite and diagonal patterns require 12 inch centers. The takeoff recalculates joist count, hangers and fasteners whenever you change spacing.

How do I know my beam and joist spans are safe?

The span check compares your species, size and spacing against IRC-style span tables and flags anything outside the table. It is a planning aid — have loaded or elevated decks reviewed locally.

How many decking boards will I need?

Board count is derived from deck area, board width and your chosen gap, plus a waste factor for cuts, stagger and picture framing.

Are the material costs accurate for my area?

Costs are regional estimates only, indexed by ZIP against national material averages. Always confirm current prices with your supplier before buying — the numbers here are for planning and budgeting, not a quote.

Do I need to confirm my measurements first?

Yes. The calculator asks you to verify key dimensions before it will produce material, cut, or shopping lists, because a single mistyped dimension changes every quantity downstream.

Home

Deck · Step 1 of 6 · The footprint

How big is the deck?

Measure the space you have to work with. Standard sizes are 12×12 for a small deck, 16×12 for a comfortable dining deck, or 20×16 for entertaining.

Length

Width (from house or edge)

Height above ground

Distance from the ground to the deck surface at the highest point.

Live estimate

Prices for your area

Enter your ZIP to re-price materials, or keep national averages.

Reviewed weekly · price book updated 2026-07-27See what changed

DIY vs. hiring a pro

Free

Save about $5,454 (63%)

building this deck yourself.

You build it$3,208

Materials only, your sweat.

A contractor builds it$8,662

Typical bids land $7,622–$10,221.

Materials: $4,010
Labor: $4,652
Est. hours: 85

Contractor figures assume a $55/hr blended labor rate (national average). Estimates only — use them to sanity-check a bid, not as a quote.

Cut-list optimizer

Free

Buy 20 boards · 5% offcut

220 linear ft purchased, 208 ft used — 12 ft ($78) left over.

13 × 2 × 8 @ 12'
Joists · 1 piece per board
0 ft scrap (0%)
6 × 6 × 6 @ 8'
Posts · 1 piece per board
12 ft scrap (25%)
1 × 2 × 10 @ 16'
Ledger board · 1 piece per board
0 ft scrap (0%)

Sheet goods and pre-built parts (Beam plies, Decking, Stair stringers, Railing) aren't cut from stock lengths — see the shopping list for those.

Estimates only. Includes a 1/8" blade kerf per cut. Measure your own site and check board lengths at the yard before buying.

Deck joist span12 ft vs 11.88 ft max span (2x8 @ 16" o.c.)
2x8 joists at 16" o.c. are rated for about 11.88 ft, but your deck width is 12 ft.
Fix: Upsize to 2x10 or 2x12 joists, tighten joist spacing to 12" o.c., or add a mid-span beam to shorten the joist run.
Deck post height / bracing3 ft vs 8 ft before bracing is typically required
3 ft of post height above grade is within typical unbraced limits.

This is an automated sanity check against published residential span guidance — estimates only, not a stamped engineering review. Local code and your inspector always govern; confirm sizing and embedment with your building department before you build.

Check a contractor bid

Free

Enter what a pro quoted you. We'll break it down against this project's materials and national labor rates.

Bid totalMaterials (optional)Labor (optional)

$3,208

incl. 10% waste

Materials

Area: 192 sqft
Footings: 6
Joists: 15
Decking boards: 58
Concrete bags: 12

Deck calculator questions

Common questions about this takeoff. All output is an estimate only — confirm quantities and prices before you buy.