Deck Joist Calculator
Figure out how many joists your deck frame needs at 12, 16 or 24 inches on center, plus rim and band joists.
Framing & Joists
Field joists16
Rim / band2
Joists needed18
Material cost$396.00
Line total$396.00
Deckworks saves the math with the line item so your customer sees exactly how you priced it.
How the math works
- 01Field joists = (run in feet × 12) ÷ on-center spacing, rounded down, plus one for the starting joist.
- 02Add your rim and band joists — usually two on a ledger-attached deck.
- 03Multiply the total by your price per joist for material cost.
Common questions
Should I frame 16in or 12in on center?
16in O.C. is standard for most decking. Go to 12in O.C. for diagonal board layouts, thin composite boards, or wherever the decking manufacturer requires it.
Does this include the beam?
No — this counts joists and rim/band members. Add beam plies as a separate line item.
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