Deck Framing Quantity Calculator

Count joist lines and planned beam or post quantities. Enter dimensions from a design your local authority accepts.

Your measurements

Editable example

Use the unit on each label. You can also type feet and inches with ft and in, or the marks on your tape measure.

Beam, post and lumber quantities

Example: replace these measurements

Plan quantities

13 joist lines

Shopping list & save options
Joist lumber before extra
156 linear ft
Beam lumber from your plan
32 linear ft
Post locations from your plan
3
Post cut lengths combined
12 ft
Joist and beam length with extra
188 linear ft

Quantity check only. Member sizes, allowable spans, loads, footings and connections must come from an accepted design.

Length 16 ftWidth 12 ft
Shown area and direction, schematic. The lines are not a cutting, fastening or installation plan.

The calculation

  1. ceil(16 × 12 ÷ 16) + 1 = 13 joist lines for a nonempty rectangle
  2. 13 × 12 = 156 linear ft of joists

How to plan the quantity

This is a quantity check for a prepared framing plan. Dividing the distance across joists by their spacing gives the bays; adding an edge line gives the joist count.

Beam lines, plies and post locations are entered from the plan. Multiplying their count by their length produces a lumber takeoff without pretending to choose an allowable span.

Keep joist size, species, grade, treatment, beam connections, ledger attachment, lateral support and footings with that plan. Each affects whether a deck design is suitable.

Before you order

  • No structural member size, allowable span, footing dimension or load approval is calculated. A quantity result cannot establish that the design is safe.
  • The AWC deck guide has stated material, load and jurisdiction limits. Ask the local building department or designer which provisions apply before ordering structural lumber.