How many board feet do you need? Enter your lumber dimensions or log measurements to calculate board feet, total cost, and weight estimates for hardwood purchases and sawmill logs.
15% typical for rough lumber milling and defects
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Last updated March 31, 2026 by our expert review team
How much area does your lumber cover at a given thickness?
Formula: sq ft = board feet / (thickness in inches / 12)
| Quarter | Rough | S2S | Common Uses |
|---|---|---|---|
| 4/4 | 1" | 13/16" | Cabinet sides, drawer fronts, small boxes |
| 5/4 | 1-1/4" | 1-1/16" | Deck boards, shelving, light furniture |
| 6/4 | 1-1/2" | 1-5/16" | Table tops, bench seats, thick shelves |
| 8/4 | 2" | 1-13/16" | Table legs, thick tops, workbenches |
| 12/4 | 3" | 2-13/16" | Turning blanks, mantels, heavy posts |
| 16/4 | 4" | 3-13/16" | Carving blocks, large turnings, timbers |
S2S = Surfaced Two Sides
Rough lumber is planed on two faces, removing about 3/16" per side. Always buy based on the rough (quarter) size and plan for the S2S final dimension.
Ehsan Ghazanfari
Licensed Structural Engineer
FISE-certified structural engineer with 11+ years designing bridges, retaining walls, and foundations. MSc from Aalto University.
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Licensed civil engineer and master plumber with 10+ years in structural design, estimation, and project management. Currently Project Engineer at Universal Robina Corporation.
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How we verify our calculatorsRetail prices for 4/4 (1" thick) lumber. Thicker stock, figured grain, and specialty cuts cost more.
Walnut runs $10 to $18/BF while poplar is $3 to $5/BF. For painted furniture, use poplar for hidden parts and save $7 to $13/BF on 60% of your material.
S2S milling removes about 3/16" per face, so 4/4 rough (1") finishes at 13/16". Buy 8/4 if you need 1.5" finished thickness.
Add 15 to 20% waste factor when ordering rough lumber. You lose material to milling, defect cutouts, and crosscutting. Our rafter calculator tells you exactly how many board feet of lumber your roof frame needs.
Our framing calculator estimates exactly how many studs and plates you need for any wall.
Kiln-dried (6 to 8% MC) costs $1 to $3/BF more than air-dried (15 to 20% MC), but air-dried stock shrinks up to 1/4" across an 8" board.
Species weight varies widely: balsa is 0.7 lbs/BF, ipe is 7.2 lbs/BF. Our 3.5 lbs/BF estimate fits oak, maple, and cherry. Building a deck? Use our deck calculator for composite and lumber estimates.
For hardwood flooring specifically, our hardwood flooring calculator estimates boxes by species with Janka hardness ratings.
NHLA FAS grade guarantees 83% clear on one face, saving hours of defect sorting vs #1 Common. Worth it for furniture projects.
Planning board and batten siding? Our board and batten calculator estimates boards, battens, and linear feet for any wall.
Enter Dimensions
Input thickness, width, and length of your lumber. Use quarter-notation presets (4/4, 8/4) or enter a custom thickness. Toggle between feet and inches for length. For rough lumber, always use nominal dimensions. A 4/4 board is entered as 1" thick even though it finishes at 13/16".
Calculate Board Feet
For lumber: BF = (T x W x L) / 144. For logs, choose Doyle, Scribner, or International 1/4" scale. The Doyle scale underestimates small log yield by 15-30% compared to International, which is why sawmills prefer buying on Doyle and selling on International. Most eastern US hardwood markets use Doyle as the default.
Get Cost Estimate
Multiply total board feet by your price per BF. Select a species to auto-fill pricing and get species-specific weight (pine: 2.3, red oak: 3.6, hickory: 4.2 lbs/BF). The waste slider adds your buffer for milling loss and defects.
Key Formulas
Lumber: BF = (T" x W" x L") / 144
Doyle: BF = (D-4)^2 x L / 16
Scribner: BF = (0.79D^2 - 2D - 4) x L / 16
Int'l 1/4": BF = (0.905D^2 - 1.62D - 9.19) x L / 16
Approximate $/BF for 4/4 FAS grade
Prices vary by region, grade, and supplier. Kiln-dried adds $1-3/BF.
What is a board foot?
144 cubic inches of lumber: 1" thick, 12" wide, 12" long. It is the standard pricing unit for hardwood in the US.
How do you calculate board feet?
Thickness (in) x Width (in) x Length (in) / 144. A 1" x 6" x 8ft board = 4.00 BF. At $8/BF, that board costs $32.
What is the Doyle log scale?
BF = (D-4)^2 x L / 16. Most common in the eastern US but underestimates yield on logs under 20" by 15 to 30%.
How much does a board foot cost in 2026?
Pine $2 to $4, poplar $3 to $5, red oak $5 to $8, cherry $7 to $12, walnut $10 to $18. FAS grade adds 20 to 40%.
What does 4/4 lumber mean?
Rough thickness in quarter-inches: 4/4 = 1", 8/4 = 2". After S2S, each face loses 3/16", so 4/4 finishes at 13/16". See the NHLA grading rules for full standards.
Board feet vs linear feet?
Linear feet measures length only. Board feet measures volume. A 2" x 6" x 1ft board is 1 linear foot but 1 board foot. Need to convert? Try our sq ft to linear ft calculator.
Which log scale gives the highest yield?
International 1/4" scale reads 10 to 20% higher than Doyle on logs under 28". Buy on Doyle, sell on International.
How much waste for rough lumber?
Plan 15 to 20% for surfacing, edging, and defects. Complex projects may waste 25 to 30%; simple slab projects as little as 10%. Planning a deck project? Factor in extra for outdoor exposure cuts.
Walnut Dining Table (8ft x 42")
44 BF + 20% waste = 53 BF | 8/4 & 12/4 walnut | $742 lumber
Top: 3 boards of 8/4 walnut, 8" wide x 8ft = 32 BF. Legs: 4 blanks of 12/4 walnut = 12 BF. At $14/BF plus $120 for finishing supplies.
Red Oak Kitchen Cabinets (10 boxes)
200 BF total | 4/4 FAS + #1 Common | $1,240 lumber
Face frames, doors, and drawer fronts: ~120 BF FAS at $7/BF = $840. Sides and shelves: 80 BF #1 Common at $5/BF = $400. Plus $180 in plywood for cabinet boxes.
Sawmill Log Purchase (White Oak)
5 logs | 450 BF Doyle (620 BF Int'l) | $1,125 at $2.50/BF
Averaging 16" diameter x 10ft. Doyle: (16-4)^2 x 10 / 16 = 90 BF per log. International scale reads $425 higher. Always confirm which scale the seller uses.
Using Finished Dimensions Instead of Nominal
Board feet use rough (nominal) size. A 4/4 board is priced at 1" thick even though it planes to 13/16". Using surfaced dimensions undercounts BF by 15 to 20%.
Forgetting Milling Waste
You lose 3/16" per face to surfacing and 1/4" per edge to jointing. A 6" rough board yields about 5.25" usable. Add 15 to 20% extra when ordering.
Comparing Prices Without Adjusting for Grade
FAS walnut at $14/BF yields 83%+ clear wood; #1 Common at $10/BF yields only 66%. The cheaper grade wastes more, making usable cost nearly identical.
Mixing Up Log Scale Methods
International 1/4" reads 20 to 30% higher than Doyle on logs under 20". Always confirm which scale the seller uses before agreeing on price.
Not Accounting for Moisture Shrinkage
Air-dried lumber (15 to 20% MC) shrinks 3 to 5% across the grain reaching indoor equilibrium. An 8" board can lose 1/4" to 3/8" width. Buy kiln-dried for furniture.
Important Disclaimer
These estimates are for planning purposes only. Actual costs vary by location, material availability, and project complexity. Always get at least 3 local quotes. This calculator does not replace professional advice.