Lumber Breakdown
Lumber Summary
Total Boards
10.00
80.00 linear feet
Total Board Feet
35.00 BF
12,800+ estimates calculated this month
Lumber Sizes, Prices & Board Foot Guide
Nominal vs. actual dimensions, 2026 price ranges, and how to calculate board feet for framing and building projects.
Understanding Lumber Dimensions
Lumber is sold by nominal size, but the actual dimensions are smaller. A 2x4, for example, is not 2 inches by 4 inches. It measures 1.5" x 3.5" after drying and surfacing at the mill. Knowing the actual dimensions matters when you are calculating board feet or planning a structural assembly.
- 2x4: Actual 1.5" x 3.5" - the workhorse of wall framing, used in virtually every residential build
- 2x6: Actual 1.5" x 5.5" - used for exterior walls (better insulation cavity), floor joists, and rafters
- 2x10 / 2x12: Actual 1.5" x 9.25" or 11.25" - used for floor joists, stair stringers, and longer-span beams
- 4x4 / 6x6: Posts for decks, fences, pergolas, and structural columns
- 1x boards: Actual 0.75" thick - used for trim, sheathing, shelving, and finish work
When you are ordering from a lumber yard or big box store, you order by the nominal size (2x4, 2x6), but your board foot calculations must use the actual dimensions to get an accurate result.
Key Takeaways
- A 2x4 actually measures 1.5" x 3.5" after milling and drying
- Nominal size is used for ordering; actual size determines board feet
- 2x6 framing provides a deeper insulation cavity than 2x4 for exterior walls
Lumber Prices in 2026
Dimensional lumber prices vary by species, grade, and where you buy. SPF (spruce-pine-fir) is the most common framing lumber in North America. Douglas fir is stronger and preferred in the West. Pressure-treated lumber costs more but is required anywhere wood contacts concrete, soil, or moisture.
- SPF 2x4 x 8': $3.50-$5.50 at big box stores, $3.00-$4.50 at a lumber yard
- SPF 2x6 x 8': $6.00-$9.00 typical range
- Douglas Fir 2x10 x 16': $18.00-$28.00 depending on grade and region
- Pressure-Treated 2x4 x 8': $7.00-$11.00 (about 2x the cost of untreated)
- Pressure-Treated 4x4 x 8': $14.00-$20.00 for deck posts
Big box vs. lumber yard: Home Depot and Lowe's are convenient for smaller quantities and carry consistent stock. A local lumber yard typically has better grades, straighter boards, and will give you a better price on larger orders (500+ board feet). For a big framing job, call a yard and ask for a quote by the unit (bundle).
Lumber prices fluctuate with housing starts, tariffs, and mill capacity. Always get a current quote for projects over $500 in material cost.
Key Takeaways
- SPF is the standard framing lumber; Douglas fir offers higher strength for the same size
- Pressure-treated lumber costs roughly twice as much and is required near moisture and soil
- Lumber yards beat big box prices on large orders and typically carry straighter stock
Calculating Board Feet
A board foot equals one square foot of lumber one inch thick - or 144 cubic inches of wood. The formula uses the actual thickness and width in inches, and the length in feet.
- Formula: Board Feet = (Actual Width x Actual Height x Length in feet) / 12
- Example: A 2x6 that is 12 feet long = (1.5 x 5.5 x 12) / 12 = 8.25 board feet
- Multiple pieces: Multiply the per-board result by quantity to get total board feet for that size
When board feet matter: Hardwood lumber (oak, maple, walnut) is always priced and sold by the board foot. For softwood framing lumber, most suppliers sell by the linear foot or by the piece at a set length. Board feet still help when you are comparing suppliers, ordering custom lengths, or tracking material costs on a job.
Softwood framing lumber is priced per piece or per linear foot at the store, but knowing your total board feet lets you compare bids apples to apples when multiple suppliers quote the same job.
Key Takeaways
- 1 board foot = 1" x 12" x 12" = 144 cubic inches of lumber
- BF = (Actual Width x Actual Height x Length in feet) / 12
- Hardwood is priced by the board foot; framing lumber is typically priced per piece or linear foot
How to Use This Calculator
Select your lumber size
Choose the nominal size from the dropdown - 2x4, 2x6, 2x10, 4x4, and more. The actual dimensions are shown for each size so you know exactly what the board foot calculation is based on.
Choose length and enter quantity
Select the board length in feet (8, 10, 12, 14, 16, or 20 ft) and enter how many boards you need at that size and length.
Enter price per board (optional)
Add the cost per board from your supplier quote or store receipt. Leave blank if you only need quantities. The calculator will show cost per board foot and per linear foot automatically.
Add more lumber sizes and review totals
Click "Add Lumber" to include additional sizes or lengths on the same project. The summary shows total boards, linear feet, board feet, and total cost across all rows.
Lumber Calculation Formulas
Board Feet = (Actual Width x Actual Height x Length) / 12
Linear Feet = Length x Quantity
Total Cost = Quantity x Price per BoardWhere:
- Actual Width
- = The real width of the board in inches after milling (e.g., a 2x4 is 1.5", a 2x6 is 1.5")
- Actual Height
- = The real height of the board in inches after milling (e.g., a 2x4 is 3.5", a 2x6 is 5.5")
- Length
- = Board length in feet (8, 10, 12, 14, 16, or 20 ft)
- Board Feet
- = Volume measure equal to 144 cubic inches; used for pricing hardwood and comparing supplier bids
- Linear Feet
- = Total length of all boards end to end; useful for decking, trim, and fencing coverage estimates
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Frequently Asked Questions
How do you calculate board feet for framing lumber?
The board foot formula uses actual dimensions: Board Feet = (Actual Width x Actual Height x Length in feet) / 12. For a 2x6 stud at 8 feet: actual width is 1.5", actual height is 5.5", so BF = (1.5 x 5.5 x 8) / 12 = 5.5 board feet per board. Multiply by quantity to get the total for that size.
What is the actual size of a 2x4?
A 2x4 measures 1.5 inches wide by 3.5 inches tall in actual dimensions. The nominal 2x4 name comes from the rough-sawn size before the board is dried and surfaced at the mill. All dimensional lumber is smaller than its nominal name: a 2x6 is actually 1.5" x 5.5", a 2x8 is 1.5" x 7.25", and so on.
How many board feet are in a 2x4 x 8 foot board?
A 2x4 that is 8 feet long contains 3.5 board feet. The calculation is (1.5 x 3.5 x 8) / 12 = 3.5 BF. At 12 feet, the same 2x4 contains 5.25 BF. Use this calculator to get the total for multiple boards and sizes in one step.
What is the difference between linear feet and board feet?
Linear feet measures only the length of a board, ignoring width and thickness. It is useful for ordering trim, decking, or fencing where you are concerned with coverage length. Board feet measures volume - it accounts for thickness, width, and length together. Hardwood lumber is priced by the board foot. Framing lumber is often priced per piece or per linear foot at the store, but board feet let you compare supplier bids on equal terms.
Should I add a waste factor to my lumber order?
Yes. For framing, add 10 to 15 percent extra to account for cuts, defects, and damaged boards. For decking or trim work, add 15 to 20 percent. For projects with many angle cuts or complex layouts, go up to 25 percent. It is always cheaper to have a few extra boards than to make a second trip to the lumber yard mid-project.
What is the best lumber for framing walls?
SPF (spruce-pine-fir) is the standard choice for interior wall framing - it is widely available, easy to work with, and cost-effective. Douglas fir is stronger and preferred in the western US, and is a better choice for floor joists and longer-span members. Use pressure-treated lumber (ground contact or above-ground rated) anywhere wood touches concrete, sits within 6 inches of soil, or is exposed to moisture long-term.
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