Lumber Calculator
Estimate board feet, lumber volume, stud counts, deck boards and total linear feet for board-foot, dimensional lumber, stud-wall, deck and custom projects — with engineering drawings and a printable PDF report.
Material cost estimate (optional)
How to estimate lumber for any project
Three quick steps from rough dimensions to board feet, pieces, linear feet & cost.
Board foot, dimensional lumber, stud wall, deck or custom — choose the mode so the right engineering drawing is shown and the correct formulas are applied for board-foot math, framing math or deck-board layout.
Thickness/width/length and quantity for board foot & custom, a standard 1×4 through 6×6 nominal size for dimensional lumber, wall length/height/spacing for stud walls, or deck length/width plus 5⁄4×6 or 2×6 deck-board size, plus a wastage allowance for cut-offs.
Total board feet, lumber volume, exact piece or stud count, total linear feet and waste added — broken out clearly with industry-standard formulas so you can order with confidence and get a quote in your local currency.
Lumber Calculator — Free & Accurate
Our lumber calculator helps framers, deck builders, general contractors and DIYers work out exactly how much lumber a job needs and what it will cost. Pick a calculation mode — board foot, dimensional lumber, stud wall, deck or custom — enter the dimensions and lumber size, and get a complete board-foot count, piece count, total linear feet and cost estimate in seconds.
Board feet are calculated using the industry-standard formula BF = (T × W × L) ÷ 12 where T and W are in inches and L is in feet. A 2×4 × 8 ft works out to (2 × 4 × 8) ÷ 12 = 5.33 BF. Stud counts use ceil(wall length × 12 ÷ spacing) + 1 plus three plate runs (1 bottom + 2 top plates). Deck-board counts use the actual face width plus a 1⁄8″ gap. Note that nominal vs. actual lumber sizes differ — a "2×4" actually measures 1.5″ × 3.5″ once dressed — so board feet use NOMINAL dims (for price/order) while volume uses ACTUAL dims (for accurate cubic feet).
An optional cost section covers lumber, hardware and labor in your local currency — USD, GBP, EUR, AUD, CAD, INR, BDT or AED — with flexible pricing units (per board foot, per piece, per linear foot, per m³, hourly, or flat-fee). Wastage allowance offers 5% Standard, 10% Recommended, 15% Complex Cuts, or a custom percentage to match the real complexity of your cuts. Everything runs in your browser — no signup, no data sent anywhere.
Why use this calculator?
Built for the board, the stud and the deck — simple, fast, and accurate.
No spreadsheets, no estimating tables. Type your thickness, width and length, hit calculate — board feet, pieces, linear feet and volume on screen.
Board foot, dimensional lumber (13 standard sizes from 1×4 to 6×6), stud wall framing, deck boards and a flexible custom mode — each with its own engineering drawing.
Board feet use (T×W×L)÷12, studs use the standard ceil+1 formula, deck boards include the 1⁄8″ gap, and volume uses real nominal-to-actual conversions (2×4 = 1.5″ × 3.5″).
Everything runs in your browser. Your project dimensions, lumber prices and cost data never leave your device.
Mix feet, inches, yards, metres and centimetres on the same job. Results show both ft³ and m³ for volume, and BF for ordering — matching whatever your supplier quotes in.
Open it on your phone right on the job site. Fully responsive, no app needed — the same compact layout works on desktop and small screens.
Related construction tools
Free, browser-based, and built the same way as the rest of the DailyToolsAI construction suite.
Frequently asked questions
The short, practical answers to the questions framers and DIYers ask most.
A board foot (BF) is the standard unit lumber yards use to price and sell rough lumber. One board foot = a piece 1″ thick × 12″ wide × 1 ft long (144 cubic inches). The formula is BF = (T × W × L) ÷ 12 where T and W are in inches and L is in feet. Examples: a 2×4 × 8 ft = (2 × 4 × 8) ÷ 12 = 5.33 BF; a 2×6 × 12 ft = (2 × 6 × 12) ÷ 12 = 12 BF; a 4×4 × 8 ft = (4 × 4 × 8) ÷ 12 = 10.67 BF. Always use NOMINAL dimensions for board feet — that's what lumber yards bill in.
Lumber is sold by its nominal (rough) size but delivered at its actual (dressed) size after planing and drying. Standard dressed sizes: 1× = 0.75″ actual, 2× = 1.5″, 4× = 3.5″, 6× = 5.5″. For widths: ×4 = 3.5″, ×6 = 5.5″, ×8 = 7.25″, ×10 = 9.25″, ×12 = 11.25″. So a "2×4" actually measures 1.5″ × 3.5″. Board feet always use nominal dimensions (that's the legal commercial standard), but volume calculations use actual dimensions for accurate cubic feet/metres.
The standard formula is studs = ceil(wall length × 12 ÷ spacing) + 1. The "+ 1" accounts for the stud at the very end of the wall. For a 12 ft wall at 16″ on-center: ceil(12 × 12 ÷ 16) + 1 = ceil(9) + 1 = 10 studs. 16″ OC is the standard for most residential framing; 24″ OC is used in advanced framing techniques to save lumber; 12″ OC is used for tall walls or extra structural rigidity. Don't forget the plates — you'll also need 3 plate runs (1 bottom + 2 top, standard double top plate) at the full wall length each, plus extra studs for corners, doorways and windows (not included in the basic count).
Number of deck boards = ceil(deck width ÷ (board face width + gap)). The standard gap is 1⁄8″ (0.125″) to allow for wood movement, drainage and debris. For a 16 ft × 12 ft deck using 5⁄4 × 6 boards (actual face width 5.5″): 12 × 12 = 144 in ÷ (5.5 + 0.125) = ceil(25.6) = 26 boards, each running the full 16 ft length = 416 linear ft. The most popular deck-board sizes are 5⁄4×6 (radius-edge decking, the most common pressure-treated profile), 2×6 (thicker, longer-spanning) and 2×4 (utility deck or boardwalk).
It depends on the complexity of the cuts. 5% Standard is enough for straight cuts and rough framing (long studs, square deck). 10% Recommended is the default for most jobs — covers the off-cuts and short-piece waste you'll generate around windows, doorways, stairs and corners. 15% Complex Cuts is sensible when there are lots of angled cuts, hip-and-valley framing, fancy trim work, or when you're working with expensive hardwoods you don't want to run short on. Always order at least one extra board beyond the calculated amount as future-repair stock since lumber yards can run out of a specific grade or species.