How many board feet is a 2x4x8?

Using actual dressed size 1.5″ × 3.5″ × 8′ → (1.5 × 3.5 × 8) ÷ 12 = 3.5 BF. Using nominal 2″ × 4″ × 8′ → (2 × 4 × 8) ÷ 12 = 5.333 BF.

How to calculate BDFt?

A meter is slightly longer — roughly 9.36% longer than a yard. (1 m ≈ 1.0936 yd)

How much is 1000 board feet of lumber?

1,000 BF is an MBF. Cost = price per BF × 1000 (varies by species, grade, and market)

How to calculate BDFt in a log?

Logs are typically scaled by rules (Doyle, Scribner, International 1/4) using small-end diameter inside bark and length. Choose the rule common in your region or buyer’s request for consistent results.

Insulation Specialist

Board Feet Calculator for Insulation

Calculate board feet for insulation materials including fiberglass, foam board, and spray foam. Get accurate coverage estimates with R-value calculations.

Insulation Calculator

Calculate board feet and coverage area for insulation materials

Insulation Type

Thickness (inches)

Width (inches)

Length (feet)

Quantity (pieces)

R-Value per inch

Common Insulation Sizes:

Fiberglass Insulation

Most common type. R-value typically 3.14 per inch. Available in batts (pre-cut) or rolls. Standard widths: 14.5" (for 16" OC studs) and 22.5" (for 24" OC).

Rigid Foam Board

Higher R-value per inch (R-5 to R-6.5). Common sizes: 4'×8' sheets in 1", 1.5", and 2" thickness. Excellent for continuous insulation applications.

Spray Foam

Highest R-value (R-6 to R-7 per inch for closed-cell). Sold by board foot coverage. One board foot covers 1 sq ft at 1" thick. Expands to fill gaps.

Frequently Asked Questions

How do I calculate insulation coverage?

Multiply width (in feet) × length (in feet) to get square footage. For board feet, multiply thickness (inches) × width (inches) × length (feet) ÷ 12.

What R-value do I need?

Depends on climate zone and application. Walls typically need R-13 to R-21, attics R-30 to R-60. Check local building codes for requirements.

How many board feet in a spray foam kit?

Common kits: 200 BF, 600 BF. One board foot covers 1 square foot at 1 inch thick. For 2" thickness, divide coverage by 2.