10% is standard. Use 15% for complex cuts.
Optional — for cost estimate.
Enter wall perimeter or a single wall length — get stud count, plate pieces, and volume.
feet
feet — leave blank for single wall
feet
Adds king/jack studs per opening
Adds trimmer/cripple studs
Lumber Planning Checklist
Covers framing layout, joist spacing, span tables, hardware, material grade, and sequencing before purchasing lumber.
Download Checklist (PDF)Planning use only. See Methodology and Data Sources. View all project checklists →
Lumber Calculator — Board Feet, Piece Count & Cost Guide
Getting lumber quantities wrong in either direction costs money. Over-order and you're paying to store leftovers; under-order and the project stalls while you wait for another delivery. The calculator above handles three common scenarios: stud framing (walls and partitions), linear boards (trim, fascia, skirting, handrail), and sheet goods (plywood and OSB). Pick the tab that matches your job, enter the dimensions, and get an instant count with waste built in.
Nominal vs actual lumber size
The label on the timber rack is not what you measure in the field. A "2×4" is actually 1.5 inches by 3.5 inches. This matters for two things: fitting into tight spaces and calculating accurate volume for board feet or cubic meters. The calculator uses actual dimensions internally so your volume figures are correct.
| Nominal size | Actual size (in) | Actual size (mm) | Common use |
|---|---|---|---|
| 1×4 | 0.75 × 3.5 | 19 × 89 | Trim, furring, shelving |
| 1×6 | 0.75 × 5.5 | 19 × 140 | Fascia, trim boards, shelving |
| 2×4 | 1.5 × 3.5 | 38 × 89 | Interior framing, most partition walls |
| 2×6 | 1.5 × 5.5 | 38 × 140 | Exterior walls (insulation depth), floor joists |
| 2×8 | 1.5 × 7.25 | 38 × 184 | Floor joists, headers, rafters |
| 2×10 | 1.5 × 9.25 | 38 × 235 | Long-span floor joists, ridge boards |
| 2×12 | 1.5 × 11.25 | 38 × 286 | Stairs, long-span headers, beams |
How to calculate board feet
Board feet is a volume unit used in North America for pricing hardwood and rough lumber. The formula is straightforward: thickness (in inches) × width (in inches) × length (in feet), divided by 12. A 2×6 that is 10 feet long is (2 × 6 × 10) ÷ 12 = 10 board feet.
For framing lumber sold by the piece (dimensional lumber), suppliers often just price per piece or per linear foot rather than per board foot. The board foot figure in this calculator is most useful when you're buying hardwood by volume or trying to compare cost between different sizes and lengths.
Sheet goods — why 32 sq ft doesn't mean 32 sq ft
A 4×8 sheet covers 32 square feet in theory. In practice, cuts at walls, around obstacles, and at room edges mean some of every sheet is wasted. A straight-run floor with no obstacles might only waste 5%. A room with multiple doorways, a bay window, or diagonal flooring might waste 15% or more. The 10% default in the calculator is conservative for most rooms, adjust it up for anything complex.
Frequently Asked Questions
Accuracy & Review
Reviewed by: Liam Santos
Liam is a framing carpenter with experience across residential stair builds, deck structures, and timber framing. He reviewed the stud count logic, board foot calculations, waste factor guidance, and sheet count methodology used in this calculator.
Last updated:
See: Methodology · Data Sources · Review Board
Related Lumber & Framing Calculators
Disclaimer: Results are for general planning only and should not be used as structural design guidance. Actual lumber quantities depend on span limits, load requirements, material grade, and building code compliance.
See Methodology and Data Sources for details.