Deck Screw Calculator
Enter your board rows and joist crossings to get a fastener count and how many boxes to buy.
From the Board Calculator's results.
Joists each row of boards crosses.
Boxes to buy
1
- Base field fasteners
- 100
- Butt-joint fasteners
- 0
- Base fasteners
- 100
- Recommended fasteners (with waste)
- 110
›Calculation details
Base field fasteners = board rows × joist crossings × fasteners per connection. If you entered your joist crossing count from the Joist Calculator, double check whether it includes the edge/end joists your boards actually cross.
Waste is applied once, after butt-joint fasteners are added, then rounded up to a whole box.
Open the Joist Calculator →How it works
Base field fasteners come from board rows × joist crossings × fasteners per connection — essentially, one count of every place a board actually meets a joist. Butt joints often need extra fasteners right at the joint, so those are added separately before waste is applied once and the total is rounded up to a whole box.
FAQ
Where do I get my “joist crossings” number?
It's how many joists a single row of boards actually crosses — often close to your total joist line count from the Joist Calculator, but check whether your board rows reach the edge joists before assuming they're equal.
I'm using hidden fastener clips — why is there no number?
Hidden systems have a different, product-specific fastener relationship that this calculator doesn't model. Check your clip manufacturer's coverage chart instead.