Do these calculators size the structure?

No. They work out quantities and lengths; member size and allowable span come from your engineer or local code span tables.

What spacing should I use for joists or studs?

16 in (40 cm) or 24 in (60 cm) on center is typical. Use what your plans or sheathing maker specify.

How much waste for lumber?

10% covers cuts and rejected pieces on most jobs.

What lumber grades are common?

No. 2 SPF, Doug-fir or southern pine, and engineered LVL or glulam for long spans.

Does framing need a permit?

New construction and additions do; check with your building department.

Solid lumber or engineered?

Engineered spans farther and stays straighter; solid lumber is cheaper in short lengths.

Carpentry & framing: calculate

Joists, rafters, stair stringers, studs, subfloor sheathing and siding. Quantities and lengths before you cut.

Calculators

Floor joist calculator
Joists, linear length, rim joist and hangers.
Rafter calculator
Rafter length and count for a gable roof.
Stair stringer calculator
Steps, riser height, total run and stringer length.
Wall stud calculator
Studs, plates and headers for a framed wall.
Subfloor sheathing calculator
Sheets, screws and adhesive for a subfloor.
Siding calculator
Siding boards and house wrap for a facade.

What do you estimate in light wood framing?

Floor joists, roof rafters, wall studs, stair stringers, subfloor sheathing and siding. Each calculator gives piece counts and lengths with waste for the order and cut list.

Member size and allowable span don't come from the calculator — they depend on loads and code span tables.

What spacing should framing use?

16 in on center is standard for floors and walls; 24 in where sheathing and finishes allow. Wider spacing saves lumber but needs thicker sheathing and may increase deflection.

Laying out from one end lands sheathing joints on framing.

How do you protect structural wood?

Use graded lumber with treatment suited to its exposure, keep it off soil, ventilate crawlspaces and seal cuts. Moisture is the main enemy — detail so water doesn't sit.

Use galvanized or stainless connectors outdoors.

Prices & Guides

FAQs

Do these calculators size the structure?: No. They work out quantities and lengths; member size and allowable span come from your engineer or local code span tables.
What spacing should I use for joists or studs?: 16 in (40 cm) or 24 in (60 cm) on center is typical. Use what your plans or sheathing maker specify.
How much waste for lumber?: 10% covers cuts and rejected pieces on most jobs.
What lumber grades are common?: No. 2 SPF, Doug-fir or southern pine, and engineered LVL or glulam for long spans.
Does framing need a permit?: New construction and additions do; check with your building department.
Solid lumber or engineered?: Engineered spans farther and stays straighter; solid lumber is cheaper in short lengths.

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