5 calculators
Deck, Fence & Carpentry Calculators
Deck, fence and carpentry calculators for posts, rails, pickets, deck boards, board feet, stair stringers and plywood sheets, with waste and cost.
Which carpentry calculator do you need?
- A fence: the fence calculator counts posts, rails, pickets or panels and post-hole concrete.
- A deck: the deck calculator works out deck boards, joists and screws.
- Hardwood or rough lumber: the board foot calculator totals board feet and cost for a lumber list.
- Stairs: the stair calculator lays out risers, treads and stringers from the total rise.
- Sheet goods: the plywood calculator counts plywood or OSB sheets for floors, walls and roofs.
Linear feet, board feet and sheets
Lumber is sold three ways. Dimensional lumber, trim and fence rails are sold by the piece or linear foot; hardwood is sold by the board foot (a volume of 144 cubic inches); plywood and OSB are sold by the sheet. Each calculator works in the unit the material is sold in, and plans cuts where it matters: deck boards and rails longer than your stock are joined, and offcuts too short to reuse are counted as waste.
Quick examples
- A 100 ft straight fence with posts every 8 ft has 13 sections and 14 posts, and two or three rails per section depending on height.
- A 12 × 16 ft deck with 5 1/2 in boards and 1/8 in gaps needs 26 rows of boards across the 12 ft width; with 16 ft boards, that is 26 boards. Joists at 16 in on center across the 16 ft length need 13 joists.
- Ten 1 × 6 hardwood boards 8 ft long are 40 board feet, the unit a lumber yard prices them in.
- A 12 × 16 ft subfloor of 4 × 8 sheets covers 192 ft²: 6 sheets exactly, or 7 with 10% for cuts.
Choosing materials
Pressure-treated pine is the budget choice for posts, framing and decking; cedar and redwood resist rot naturally and weather to gray; composite and PVC decking cost more up front but need little maintenance and may require closer joist spacing. Use ground-contact rated lumber for posts and anything near the soil, and check that fasteners and hangers are rated for treated wood.
Planning outdoor carpentry
- Call before you dig for fence posts and deck footings, so underground utilities are marked.
- Check permits and rules: decks, tall fences and stairs often need permits and must meet local code.
- Buy a little extra: 5–10% for cuts, splits and picking the best boards.
- Use the right fasteners: hot-dipped galvanized or stainless fasteners for pressure-treated wood outdoors.
What these calculators do not do
They count materials and lay out geometry. They do not size joists, beams, posts or footings, or confirm stair and railing code compliance. Structural sizes come from code span tables, an engineer or your building department.