Free woodworking and lumber calculators
Board feet, stair stringers, deck boards, rafters and cut lists, worked out before you head to the lumberyard.
What are you working on?
Pick your project — each one opens its own calculator, then the next steps.
- DeckDeck boards, linear footage and screws for a rectangular deck.
- StairsHow many steps, the height of each step, the run and stringer length — from the height of your deck or floor.
- FencePickets, posts and rails for a straight run of wood fence.
- Wall panelingRows, linear feet and boards of shiplap for a wall, from the board’s coverage width.
- Roof framingCommon rafter length from span and pitch, with overhang, the board length to buy, birdsmouth, HAP and ridge height.
- Shelves & furnitureHow many boards to buy for any list of pieces, and where to cut each one — plus a rough hardwood takeoff in board feet.
- Buying hardwoodBoard feet for one board or a stack, with volume and cost per board foot.
- Trim & framesMiter saw angle and piece lengths for a square, hexagon, octagon or any n-sided frame — or any single corner.
Every calculator, by project
Lumber & board feet 6
Plywood, stain & finish 2
Firewood & logs 2
Stairs, decks & fences 7
Angles, frames & shelves 6
Framing & roofing 4
Popular sizes, already worked out
- How many board feet in a 2x4x85.33 board feet
- How many board feet in a 2x6x88 board feet
- Board feet in a 4/4 hardwood board, 8 in × 8 ft5.33 bd ft (yard tally: 5)
- What is the actual size of a 2x41-1/2 × 3-1/2 in
- How many steps for a 3 ft deck5 risers
- How far can a 2x8 deck joist span11 ft 10 in
- How much wood is in a face cord or rick0.33 cords
- What miter angle for an octagon22.5 degrees
- Crown molding miter angle for a 90° inside corner (38° crown)31.6 degrees
- How much does a sheet of 3/4 plywood weigh73.7 lb
- How many sheets of plywood for a 12x12 floor5 sheets
- How many 24 in pieces from an 8 ft board3 pieces
- How many balusters for a 6 ft railing section13 balusters
- Rafter length for a 12 ft shed at 4/1287-3/4 in (7 ft 3-3/4 in)
- How much does a cord of oak weigh3,587 lb
Guides
- Woodworking and lumber words, explainedPlain-English meanings of board foot, nominal vs actual, 4/4, S4S, kerf, on center, joist, ledger, stringer, riser, miter vs bevel, face cord and more.
- What is a board foot? How lumber is measured and pricedA board foot is 144 cubic inches of wood. How to calculate it, why softwood uses nominal size and hardwood uses quarters, and how yards price by the MBF.
- Board foot chart for common lumber sizesBoard feet for every common lumber size, 1×4 to 6×6 at 8 to 20 ft, plus a 4/4–8/4 hardwood chart per linear foot and how to read both.
- Nominal vs actual lumber sizes: the full chartWhy a 2×4 is 1½ × 3½ in: the full chart of nominal and actual lumber sizes in inches and mm, plus plywood, hardwood quarters and metric timber.
- Hardwood buying guide: 4/4, S2S, rough lumber and grades explainedHow to buy hardwood lumber: quarter thickness (4/4, 8/4), rough vs S2S vs S4S, grades like FAS and #1 Common, moisture, and how much extra to buy.
- How to lay out and cut stair stringers, step by stepMeasure total rise, work out risers and treads, and mark a stair stringer with a framing square and stair gauges. With typical code limits to check.
Frequently asked questions
How do I calculate board feet?
Multiply thickness (in) × width (in) × length (ft) and divide by 12. A 2×6 that is 10 ft long is 2 × 6 × 10 ÷ 12 = 10 board feet. Use the size the lumber is sold by: nominal for construction lumber, rough thickness (4/4, 8/4) for hardwood. The board foot chart has the common sizes worked out.
Why is a 2×4 not 2 by 4 inches?
The name is the nominal size — roughly the size it was sawn at before drying and planing. A standard dry 2×4 measures 1½ × 3½ in. The lumber dimensions calculator lists actual sizes for common lumber.
How big is a cord of firewood?
A full cord is 128 cubic feet of stacked wood — 4 ft high, 4 ft deep and 8 ft long. A face cord is one 4 × 8 ft row of whatever piece length is cut, usually 16 in, which is a third of a cord.
Do the calculators work in metric?
Yes. Every calculator has a US / metric toggle and converts your entries when you switch. Board feet and cords are North American units, so those calculators also show cubic metres.
Are the results exact?
They are planning estimates. Real boards vary in size, density and moisture, and yards round their tallies in their own ways. Buy a little extra, and for anything structural — stairs, decks, shelving that carries real weight — follow your local building code and the manufacturer’s instructions.
Where do the wood density, stiffness and shrinkage figures come from?
They are typical values for wood at about 12% moisture content from the USDA Forest Products Laboratory’s Wood Handbook (FPL-GTR-282) and The Wood Database. Individual boards commonly differ by 10% or more. Code limits — stair risers, guard heights, deck joist spans — come from the 2021 International Residential Code; each calculator lists its sources at the bottom of the page.