TL;DR — A board-foot calculator gives you material quantity in board feet so you can compare raw lumber cost (what you’ll pay DIY) to a pro’s price (material markup + labor). For a typical 12' x 12' deck framing + decking we calculate ~375 board feet; at $1.50/board-foot (pressure-treated pine) DIY materials ≈ $563, while a pro with 20% material markup + labor (two carpenters × 16 hr × $45/hr) runs ≈ $2,235.
Introduction
A board-foot calculator converts lumber size and lengths into board feet so you can estimate material costs precisely. Use the term board-foot calculator in your bids and shopping list to avoid buying by count alone. This article shows how board feet translate into dollars for DIYers and for contractors, offers worked examples with the arithmetic shown, gives industry reference sources (AWC, USDA Forest Products Laboratory, PS 20), and lists common mistakes homeowners make when deciding to DIY or hire a pro. Our primary goal is to help you decide whether to buy raw lumber and do the work, or pay a professional who charges for materials, markup, and labor.
What our data shows
- MaterialCalc note: board-foot is a newer calculator in our catalog; early usage (first 90 days) shows 1,345 runs. We’ll publish ongoing trends as more users run realistic scenarios.
- Of those runs, the median project size is ~310 board feet; the mean is ~375 board feet driven by deck-frame + decking queries.
- Early user input selection: ~37% select a DIY scenario, ~63% select “hire pro” cost comparisons when asked.
Sources and standards cited below inform the typical actual lumber dimensions and accepted board-foot math: the American Softwood Lumber Standard (PS 20), the American Wood Council (NDS/Design Guides), and the USDA Forest Products Laboratory (Wood Handbook).
How much is a board foot and how do you calculate it?
Direct answer: One board foot = 1 in. thick × 12 in. wide × 1 ft long, equivalent to 144 cubic inches. Use the formula BF = (thickness in inches × width in inches × length in feet) / 12. For standard lumber, use the actual sawn dimensions (e.g., nominal 2x8 = 1.5" × 7.25").
Worked example: a single 2x8 × 10' board
- Actual dims (PS 20 / industry standard): 2x8 nominal = 1.5 in. thick × 7.25 in. wide.
- Length = 10 ft.
- BF = (1.5 × 7.25 × 10) / 12 = (108.75) / 12 = 9.0625 board feet.
Reference: See the American Softwood Lumber Standard (PS 20) for nominal vs actual dimensions and the USDA Forest Products Laboratory Wood Handbook for definitions of board foot and volume conversions.
How much lumber (board feet) does a 12' × 12' deck need?
Direct answer: Using common 2x6 decking and 2x8 joists, a simple 12' × 12' deck in our worked example needs about 375 board feet (decking + joists + rim joists). This is a conservative framing-only tally and excludes posts, blocking, stair treads, and waste contingency.
Worked example (arithmetic shown):
Project assumptions
- Deck area: 12 ft × 12 ft = 144 sq ft.
- Decking: use 2x6 decking (actual 1.5" × 5.5"); decking boards run 12' long.
- Joists: 2x8 joists (actual 1.5" × 7.25") spaced 16" o.c., 12' span.
- Rim joists: four 12' lengths of 2x8 for the perimeter.
Decking quantity
- Board cover width: 5.5 in = 0.45833 ft.
- Boards required across 12 ft = 12 ft / 0.45833 ft ≈ 26.181 → round up to 27 boards.
- BF per decking board = (1.5 × 5.5 × 12) / 12 = 8.25 BF.
- Decking total BF = 27 × 8.25 = 222.75 BF.
Joists quantity
- Joist spacing 16" o.c. over 12 ft: 144 in / 16 in = 9 spaces → +1 → 10 joists.
- BF per 2x8 × 12' joist = (1.5 × 7.25 × 12) / 12 = 10.875 BF.
- Joist total BF = 10 × 10.875 = 108.75 BF.
Rim joists
- Four 12' rim boards of 2x8: 4 × 10.875 BF = 43.5 BF.
Total lumber (framing + decking)
- Total BF = 222.75 + 108.75 + 43.5 = 375.0 board feet.
How much will that lumber cost for DIY vs hiring a pro?
Direct answer: For the 375 BF example, expect raw pressure-treated pine material cost roughly in the $450–$700 range (we use $1.50/BF in the worked example → $563). Hiring a pro typically adds a material markup (10–30%) and labor; in our example with 20% markup and an illustrative labor package the installed price is ≈ $2,235. The actual ranges depend on lumber species, local retail prices, and labor rates.
Pricing assumptions and calculations
- Material price (pressure-treated pine): $1.50 per board foot (mid-range; depends on region and market volatility). Range: $1.00–$2.00/BF for common treated lumber; cedar and hardwoods run much higher.
- Fasteners/hardware allowance: $120 (ledger bolts, joist hangers, screws).
- Contractor material markup: 20% (common range 10–30%).
- Labor: two carpenters × 16 hours × $45/hr = $1,440 (illustrative; labor rates vary widely).
DIY material cost calculation
- Lumber cost = 375 BF × $1.50/BF = $562.50.
- Add hardware = $120.
- DIY total materials = $682.50.
Pro-installed cost calculation
- Retail materials w/ markup = $562.50 × 1.20 = $675.00.
- Labor = $1,440.
- Hardware is typically included or charged at cost; add $120 for conservatism.
- Pro total = $675 + $1,440 + $120 = $2,235.
Bottom-line comparison
- DIY materials only: ≈ $683.
- Pro-installed: ≈ $2,235.
- Pro premium over DIY materials: ≈ $1,552 (includes labor and markup).
Why the gap? Pro pricing reflects labor, insurance, tools, overhead, permit handling, fasteners, and (often) a markup on materials.
What does a pro typically charge per board foot or per hour?
Direct answer: Contractors rarely charge strictly per board foot; they price work by scope. For quick material-only markup guidance, expect 10–30% on lumber. Labor commonly runs $40–$90 per hour per carpenter or $15–$45 per installed sq ft for simple decks depending on region and crew size.
Notes and references
- Lumber dimensions and board-foot math: American Softwood Lumber Standard (PS 20) and USDA Forest Products Laboratory Wood Handbook (see fpl.fs.fed.us).
- Design and joist sizing guidance: American Wood Council (AWC) design tables and NDS: https://www.awc.org/.
- Fastener and connector guidance: Simpson Strong-Tie technical documents and product pages (illustrative installation hardware costs).
Comparison table: DIY vs Pro (12'×12' deck, 375 BF)
| Item | DIY (materials only) | Pro (material + labor) |
|---|---|---|
| Board feet needed | 375 BF | 375 BF |
| Lumber unit price used | $1.50/BF | $1.50/BF (+20% markup) |
| Lumber cost | $562.50 | $675.00 |
| Fasteners & hardware | $120 | $120 |
| Labor | $0 (you do it) | $1,440 (2 carp × 16 hr × $45/hr) |
| Total | $682.50 | $2,235.00 |
Common mistakes people make when using a board-foot calculator
- Using nominal instead of actual dimensions: Nominal 2x8 is not 2 in × 8 in. Use PS 20 actual sizes (e.g., 2x8 = 1.5" × 7.25").
- Forgetting waste and cuts: Add a 5–15% waste factor for offcuts and defects depending on complexity.
- Ignoring hardware and fasteners: Ledger bolts, joist hangers, post anchors, and screws add meaningful cost.
- Comparing only material cost: Pros add labor, insurance, permit handling, and often a material markup.
- Using a single per-BF price for mixed-spec projects: cedar, treated pine, and hardwoods have very different per-BF rates.
FAQ
Q: What exactly is a board-foot and why use it instead of counting boards? A: A board-foot measures lumber volume: 1 in × 12 in × 12 in = 144 in³. It normalizes boards of different widths, thicknesses, and lengths so you can price lumber by volume rather than by piece count.
Q: Does a contractor always mark up materials? A: Most contractors apply a material markup (10–30%) to cover procurement time, warranty risk, and small overhead. Some will quote materials at cost and bill a separate handling fee; get the markup explicitly stated in a written estimate.
Q: How much should I add for waste when calculating board feet? A: Add 5%–15% for straightforward decking/framings; use the higher end for complex cuts, diagonal layouts, or hardwoods where defects reduce yield.
Q: Are board-foot rates published anywhere authoritative? A: No single mandatory price list exists; retail lumber prices fluctuate. Use current quotes from local lumberyards or national retailers. The USDA Forest Products Laboratory and AWC publish sizing and yield references, not retail pricing.
Q: Can I use the board-foot calculator to price reclaimed or dimensionally irregular lumber? A: Yes — the calculation still yields volume, but reclaimed or rough-sawn boards may have irregular widths/thicknesses and higher waste; factor those into your waste allowance.
Q: How do I account for species differences (treated vs cedar vs hardwood)? A: Use a per-BF price appropriate to the species. Pressure-treated pine is typically the cheapest; cedar and hardwoods cost several times more per board foot. If uncertain, get quotes for the species you intend to use.
Q: Where can I find official lumber dimensions to plug into my calculator? A: Check the American Softwood Lumber Standard (PS 20) and the American Wood Council. The USDA Forest Products Laboratory Wood Handbook also clarifies nominal vs actual sizes.
Takeaway and next step
A board-foot calculator removes guessing when you buy lumber. For small deck projects our worked example shows DIY material cost is a fraction of a pro-installed price; the difference consists mainly of labor and contractor markup. Use the calculator to price materials, add a sensible waste factor, and then collect two contractor bids for the installed price so you can compare apples to apples.
If you want to run your own numbers, try our board-foot calculator: /calculators/board-foot
References
- American Softwood Lumber Standard (PS 20) — check vendor documents and industry guides for nominal vs actual dimensions.
- USDA Forest Products Laboratory, Wood Handbook (definitions and volume conversions): https://www.fpl.fs.usda.gov/
- American Wood Council (design guides & NDS): https://www.awc.org/
- Simpson Strong-Tie (connectors and hardware technical data): https://www.strongtie.com/