Lumber Calculator

How many board feet of lumber do I need? Use the industry formula pieces × (thickness″ × width″ × length ft) ÷ 12 with nominal dimensions. Ten pieces of 2×4×8 ft equal 53.3 board feet (80 linear feet). Enter count and size below for an instant total.

Reviewed / updated August 2026

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Your inputs

ft

Common stock: 8, 10, 12, or 16 ft

in

e.g. 2 for a 2×4

in

e.g. 4 for a 2×4

Result

Board feet

53.3

80 linear ft · nominal 2×4

Board feet
53.3
Linear feet
80

10 pieces of 2×4×8 ft is 53.3 board feet (nominal), or 80 linear feet total.

What-if: 2×4 vs 2×6 (same count & length)

SizeBoard ftLinear ft
2×453.380
2×68080

Suggested next step

Confirm actual (dressed) thickness at the rack if fit is tight — board feet still use nominal sizes.

How the lumber calculation works

Lumber yards quote many structural boards in board feet (BF) using nominal thickness and width:

  1. Board feet = pieces × (thickness in × width in × length ft) ÷ 12
  2. Linear feet = pieces × length ft

A 2×6 has 50% more board feet than a 2×4 of the same length and count — compare both in the what-if table. Results update as you type. Use the Fence Calculator for pickets and posts, or the Roofing Calculator when framing ties into a roof job. Browse every DIY estimator on the Home Improvement hub.

Source note: The ÷12 board-foot formula is the North American lumber-industry standard for nominal softwood. Updated August 2026.

Worked example

10 pieces, 2×4, 8 ft long:

  1. Board feet = 10 × (2 × 4 × 8) ÷ 12 = 10 × 5.333… = 53.3 BF
  2. Linear feet = 10 × 8 = 80 ft

Those are the default inputs. Switching the same order to 2×6 raises board feet to 80 BF while linear feet stay 80 — useful when comparing stud or joist options.

Methodology and notes

This tool does not convert to metric, grade stamps, or treatment types. Add a cull/cut allowance if your cut list wastes short offcuts. Confirm stock length availability (8, 10, 12, 16 ft) at your yard before finalizing an order.

Frequently asked questions

How do you calculate board feet?

Board feet = number of pieces × thickness (in) × width (in) × length (ft) ÷ 12. Example: 10 × 2 × 4 × 8 ÷ 12 = 53.33 board feet.

What is a board foot?

One board foot is the volume of a board 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches) using nominal lumber sizes.

Do I use nominal or actual dimensions?

Board-foot math uses nominal sizes (a “2×4” as 2″ × 4″). Actual dressed lumber is smaller; pricing and BF quotes still follow the nominal rule.

How many board feet in a 2×4×8?

One 2×4×8 is (2 × 4 × 8) ÷ 12 = 5.33 board feet. Ten of them are 53.3 board feet.

What is linear feet vs board feet?

Linear feet is pieces × length (how much running length you buy). Board feet measures volume for pricing thicker or wider stock.

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