Deck fastener calculator
Deck area, board width, joist spacing and screws per crossing: you get boxes of stainless deck screws or hidden clips.
Purchase quantity
200 unit
Net measurement: 200 unit · Waste 5 %
- Stainless deck screws3 box
- Hidden clips (alternative)3 box
Your prices per language/currency. Used when you enable “Use my prices” in calculators. My prices →
How it's calculated (visible formula)
crossings = area × (1 ÷ (board + ¼ in gap)) × (1 ÷ joist spacing); screws = crossings × screws per crossing
- Net geometric measurement, no waste.
- Adjustable waste % for cuts and breakage.
- Purchase rounded up to sellable units (boxes, bags, buckets, boards).
How to calculate it, step by step
- Measure the deck area.
- Enter board width and joist spacing.
- Work out board-to-joist crossings per area.
- Multiply by screws per crossing (or one clip per crossing).
- Add 5% and round up to boxes.
Worked example: 130 sq ft, 5½ in boards, joists 16 in OC, 2 screws
- ≈ 2.1 rows per ft × 0.75 joists per ft
- ≈ 200 crossings
- 400 screws + 5% = 420
→ 3 boxes of 200 screws (or 3 boxes of 100 clips).
Common mistakes
- Using galvanized screws in tannin-rich woods — they stain.
- Not pre-drilling dense hardwoods.
- Forgetting joist-to-support fasteners.
Pro tips
- Pre-drill and countersink in hardwoods to prevent splits.
- Keep screws ⅝–¾ in from board edges.
- Use the decking maker's clips to keep the warranty.
- Snap a chalk line for straight screw rows.
From calculation to quote
Add labour, overhead and your margin, and generate the professional PDF.
FAQs
- How many deck screws per square foot?
- About 3–3.5 with 5½ in boards on 16 in joists.
- Which screw should I use?
- Stainless (305/316 near salt water), about #10 × 2½ in.
- How many hidden clips per square foot?
- One per crossing — about 1.6 per sq ft in that layout.
- 304 or 316 stainless?
- 304 for general use; 316 near salt water or chlorinated pools.
- How long should deck screws be?
- At least 2½ times the board thickness.
- Can I use nails?
- Not recommended — they back out with moisture cycles.
Sources and standards
Maintained by Srikanta M · Formula v1.0.0 · Verified 2026-09-10 · Updated 2026-09-10 · Limits: quantity estimation, not structural design or site supervision.