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Lumber Calculator

Calculate board feet, linear feet, pieces needed, and cost estimates for any lumber project. Includes common sizes and 2026 pricing.

🪵 Choose Your Calculation

Board Feet
Pieces Needed
Wall Framing
Deck Boards
Pro Tip: Always add 10–15% waste for cuts, defects, and mistakes. For angled cuts (like deck board patterns), add 20%. Buy a few extra boards — returning unused lumber is easier than making a second trip.

How to Calculate Board Feet: Complete Guide

Board feet is the standard unit for measuring and pricing hardwood lumber. Understanding it saves you money and prevents ordering mistakes.

The Board Foot Formula

Board Feet = (Thickness × Width × Length) ÷ 12

Where thickness and width are in inches, and length is in feet. One board foot = 144 cubic inches of wood (1" × 12" × 12").

Quick Board Foot Reference

SizePer 8 ftPer 10 ftPer 12 ftPer 16 ft
1×42.67 BF3.33 BF4.00 BF5.33 BF
1×64.00 BF5.00 BF6.00 BF8.00 BF
1×85.33 BF6.67 BF8.00 BF10.67 BF
1×128.00 BF10.00 BF12.00 BF16.00 BF
2×45.33 BF6.67 BF8.00 BF10.67 BF
2×68.00 BF10.00 BF12.00 BF16.00 BF
2×810.67 BF13.33 BF16.00 BF21.33 BF
2×1013.33 BF16.67 BF20.00 BF26.67 BF
2×1216.00 BF20.00 BF24.00 BF32.00 BF
4×410.67 BF13.33 BF16.00 BF21.33 BF

Nominal vs. Actual Lumber Sizes

Nominal SizeActual SizeDifference
1×4¾" × 3½"Planed ¼" + ½"
1×6¾" × 5½"
1×8¾" × 7¼"
1×12¾" × 11¼"
2×41½" × 3½"Planed ½" each side
2×61½" × 5½"
2×81½" × 7¼"
2×101½" × 9¼"
2×121½" × 11¼"
4×43½" × 3½"
6×65½" × 5½"

Important: Board feet for pricing uses nominal dimensions. When calculating actual coverage (e.g., deck boards), use actual dimensions.

2026 Lumber Pricing Guide

Lumber TypeSizePrice Range (8 ft)
SPF Stud2×4×8$3.50–$5.50
SPF Framing2×6×8$5.50–$8.00
SPF Framing2×4×16$7.00–$11.00
Pressure Treated2×6×8$9.00–$14.00
Pressure Treated4×4×8$12.00–$18.00
Cedar2×6×8$14.00–$22.00
5/4 Deck Board (PT)5/4×6×12$12.00–$18.00
Oak (hardwood)Per BF$5.00–$10.00
Walnut (hardwood)Per BF$12.00–$20.00
Maple (hardwood)Per BF$6.00–$12.00
Cherry (hardwood)Per BF$7.00–$14.00

5 Lumber Buying Mistakes to Avoid

  1. Not checking boards for straightness. Sight down each board before buying. Twist, bow, and cup are common — especially in big-box stores. A crooked stud is worthless.
  2. Buying green (wet) lumber for finish work. Kiln-dried (KD) lumber has ~12% moisture; green lumber has 30%+. Green wood shrinks, warps, and cracks as it dries. Always use KD for interior work.
  3. Skipping the waste factor. Every cut generates waste. Miter cuts waste more than square cuts. Add 10% for straight cuts, 15–20% for angles.
  4. Not comparing board foot pricing. A $12 board isn't always cheaper than a $15 board. Calculate the price per board foot to compare across sizes and species.
  5. Ignoring lumber grades. #1 grade has fewer knots and defects than #2. For visible work (trim, furniture), pay up for #1 or Select. For framing behind walls, #2 is fine.

Lumber Grades Explained

GradeQualityBest For
Select / ClearFew or no knotsTrim, cabinetry, furniture
#1 (Construction)Small, tight knotsExposed framing, shelving
#2 (Standard)Larger knots, minor defectsGeneral framing, hidden structure
#3 (Utility)Large knots, some defectsBlocking, bracing, temporary
Stud GradeSpecial #2 for vertical loadsWall studs specifically

Hardwood grades use a different system: FAS (First and Seconds) is the best, followed by #1 Common and #2 Common. FAS boards must be at least 6" wide and 8' long with 83%+ clear area.

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