Framing & lumber calculators

Stud Calculator

Enter the wall length and height, spacing and openings to get every stud, plate and header drawn in place with a cut list.

Framing Calculator

Add each wall with its doors and windows to get studs, plates, sized headers, sheathing and nails in one material list.

Beam Span Calculator

Pick the wall, the load it carries, the building width and snow load to get the smallest header for your opening and the full span table.

Board Foot Calculator

List your boards by thickness, width, length and count; get board feet, volume and cost.

Plywood Calculator

Get sheets of plywood or OSB for a floor, walls or roof, or lay out a cabinet cut list on 4 × 8 sheets.

Lumber Calculator

List the pieces your project needs by size and length; get the boards to buy, a cutting diagram and board feet.

Log Board Foot Calculator

Enter the small-end diameter and length of a log, or a tree's DBH and logs; compare all three log rules.

Floor Joist Span Calculator & Span Chart

Floor joist span is read from the IRC table for your lumber, size and spacing: a No. 2 Douglas fir-larch 2x10 at 16 in on center spans 15 ft 7 in under a 40 psf living-area floor.

Ceiling Joist Span Calculator & Span Table

Ceiling joist span is read from the IRC table for your lumber, size and spacing: a No. 2 Douglas fir-larch 2x6 at 16 in on center spans 17 ft 8 in under an attic with no storage.

Header Span Calculator & Garage Door Header Size

Header size = the smallest built-up lumber whose IRC table span covers the opening: a 9 ft garage door in a 24 ft wide house with a 30 psf snow load needs a 3-2x12 header.

LVL Beam Calculator & Size Chart

LVL beam size is the shallowest depth whose bending, shear and sag all pass: a 12 ft floor beam with a 10 ft tributary width at 40 psf live and 10 psf dead needs a 2-ply 1¾ x 9½ in LVL.

Steel Beam Calculator: W-Shape Size for Your Span

Steel beam size is the lightest W-shape whose bending, shear and sag all pass: a 14 ft span with 400 plf live and 100 plf dead load takes a W8x13.

Beam Deflection Calculator

Beam deflection = 5 × w × L⁴ ÷ (384 × E × I) for a uniform load on a simple span: two 2x10s of Douglas fir-larch No. 2 carrying 100 plf over 12 ft sag 0.15 in, about L/977.

I-Beam Size Calculator & Size Chart

I-beam weight = the pounds per foot in the shape name times the length: a W12x26 weighs 26 lb per foot, so 12 ft of it weighs 312 lb.

Shelf Sag Calculator (Sagulator)

Shelf sag = 5 × load × span⁴ ÷ (384 × E × I): a 36 in shelf of ¾ in grade 130 MDF holding 25 psf sags 0.35 in, about L/104, and fails.