Deck Material Calculator
Calculate decking, framing lumber, posts, concrete, fasteners, and railing materials for any deck size.
Ground to top of deck frame
0 = auto (perimeter minus house side)
Estimated Material Cost
$1,244
192 sqft · Pressure Treated · $6/sqft
Deck Boards
| Deck Area | 192 sqft |
| Boards Per Row (5.5" (nominal 2×6)) | 27 |
| Total Deck Board LF (w/ 10% waste) | 475 lf |
| Decking Cost (475 lf × $1.50) | $713 |
Framing
| Joists (16" OC (standard)) | 13 × 12 ft = 156 lf |
| Beams (doubled, every 8 ft) | 3 × 16 ft = 48 lf |
| Posts 6×6 (5.0 ft ea, 2 ft in ground) | 9 posts = 45 lf |
| Total Framing LF | 249 lf |
| Concrete 80 lb Bags (2 per post) | 18 |
| Framing Cost (249 lf × $1.50) | $374 |
Fasteners & Railing
| Deck Screws / Nails (10 lbs) | $50 |
| Concrete (18 bags × $6) | $108 |
| Railing Posts (every 6 ft) | 8 posts |
| Rails (top + bottom) | 80 lf |
| Balusters (4" spacing) | 107 |
| Cost Summary | Amount |
|---|---|
| Decking (Pressure Treated) | $713 |
| Framing Lumber (PT) | $374 |
| Concrete | $108 |
| Fasteners | $50 |
| Total Material Cost | $1,244 |
| Cost Per Sqft | $6/sqft |
Mike Callahan:Composite decking is 3× the material cost of PT but zero maintenance for 25 years. Do the math on 25 years of staining PT every 2–3 years ($2–3/sqft per application) and composite wins. But always frame with pressure treated, even under composite — composite joists don’t exist.
Boards per row = deck width ÷ board width. Total LF = boards × length × 1.10 waste. Joists = length ÷ spacing + 1, spanning the width. Beams every 8 ft, doubled 2×10. Posts at each beam intersection, extending deck height + 2 ft underground. Concrete at 2 bags (80 lb) per post. Fasteners at 5 lbs/100 sqft for screws or 3 hidden clips/sqft for composite. Framing priced at $1.50/lf (pressure treated). Railing posts every 6 ft, balusters at 4-inch spacing. Costs are material only — labor typically adds 50–100% for professional installation.
Frequently Asked Questions
How many deck boards do I need?
Divide the deck width by the board width to get boards per row, then multiply by the deck length for total linear feet. Add 10% for waste from cuts and defective boards. For a 16×12 ft deck with 5.5-inch boards: 12 ft ÷ 0.458 ft = 27 boards per row × 16 ft = 432 lf, plus 10% waste = ~475 lf. If buying 16-ft boards, that’s 27 boards with minimal waste.
16-inch vs 12-inch joist spacing?
Standard 16-inch on-center spacing works for most wood decking with 2×6 boards. Use 12-inch spacing for composite and PVC decking (most manufacturers require it for warranty), diagonal board patterns, hot tub or heavy-load areas, and spans over 10 feet between beams. The 12-inch spacing uses about 33% more joist lumber but prevents bounce and flex.
Pressure treated vs composite cost over time?
Pressure treated lumber costs $1.50–2.00/lf upfront but needs staining every 2–3 years at $2–3/sqft. Over 25 years, a 200 sqft PT deck costs roughly $600 in lumber + $4,000–6,000 in stain and labor. Composite costs $5–7/lf upfront with zero maintenance — the 25-year total is often comparable or less than PT when you factor in your time and materials. PT also has a 15–20 year lifespan vs 25–30 for composite.
How deep should deck post holes be?
Deck post holes must extend below the frost line, which varies by region: 12 inches in the South, 36–48 inches in the Northern US and Canada. As a minimum, IRC code requires footings at least 12 inches below undisturbed ground. Most jurisdictions require 42–48 inches for frost protection. The hole diameter should be 3× the post width — for a 6×6 post, dig a 16–18 inch diameter hole. Always check local code before digging.