How many deck screws do I need?
Deck board thickness
Measure the actual board, not the nominal size — a 2x8 runs about 1-1/2" thick.
12–16 typical.
Sizes the drill bits.
On center, inches.
You need
1,100screws
- Cross members
- 37
- Screws needed
- 1,036
- Screw
- 2-1/2" 5/16"-18
- Driver bit
- T40
Two screws per board at every cross member. Fasteners sell in 100s, so 1,036 rounds up to 1,100.
Bits you'll wear out
- T40 driver bits
- 6
- 9/32" drill bits
- 1 set
- Countersink
- 1
One driver bit per 200 screws. One 12-pack of drills per 800 SF of deck, one countersink per 4,000 SF — you're covering 384 SF.
Trailer deck screw sizing chart
| Board thickness | Screw length | Thread | Driver bit | Pilot drill |
|---|---|---|---|---|
| 1-1/8" and under | 2" | 1/4"-20 | T30 | 7/32" |
| 1-1/8" to 1-5/8" | 2-1/2" | 5/16"-18 | T40 | 9/32" |
| 1-5/8" to 1-7/8" | 3" | 5/16"-18 | T40 | 9/32" |
| 1-7/8" to 2-1/2" | 3-1/2" | 5/16"-18 | T40 | 9/32" |
| 2-1/2" to 3" | 4" | 5/16"-18 | T40 | 9/32" |
Pilot drill runs about 1/32" under the screw's major diameter. Plan on one driver bit per 200 screws, one 12-pack of pilot drills per 800 SF of deck, and one countersink per 4,000 SF. Thicker than 3"? Call 855.274.8664.