Wood Screw Size Chart: Complete Guide to Types, Gauges & Lengths (2026)
Wood screw sizing is confusing because gauge numbers run backwards from what you expect — a #14 screw is larger than a #6. This guide covers everything: gauge to diameter conversion, correct lengths, pilot hole sizes, and which type to use for every application.
Quick answer: For most general woodworking, a #8 screw is the versatile default — go #6 for light trim and #10-#12 for heavy structural framing. Pilot-drill in hardwood and near any edge; screws #10 and larger need a pilot hole in softwood too. The screw should penetrate at least two-thirds of its length into the receiving piece.
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Wood Screw Gauge to Diameter Chart
| Gauge | Shank Diameter | Pilot Hole (Softwood) | Pilot Hole (Hardwood) | Clearance Hole |
|---|---|---|---|---|
| #4 | 0.112" | 3/64" | 1/16" | 1/8" |
| #6 | 0.138" | 5/64" | 3/32" | 9/64" |
| #8 | 0.164" | 7/64" | 1/8" | 11/64" |
| #10 | 0.190" | 9/64" | 9/64" | 3/16" |
| #12 | 0.216" | 5/32" | 11/64" | 7/32" |
| #14 | 0.242" | 11/64" | 3/16" | 1/4" |
The pilot sizes above follow the common trade convention: softwood pilots at roughly 85% of the thread’s root diameter, hardwood pilots at the root diameter itself. Root diameter is the solid core under the threads, not the outside of the threads. Other charts use tighter or looser ratios, which is why published numbers differ by a drill size — see the full pilot hole guide for the detail.
Wood Screw Length Guide
The rule of thumb: the screw should penetrate at least two-thirds of its total length into the receiving piece. For a 2 inch screw through 3/4 inch material, that means 1-1/4 inch of penetration — acceptable. For structural applications use three-quarters penetration.
| Top Material | Min Screw Length | Recommended |
|---|---|---|
| 1/2" plywood | 1-1/4" | 1-1/2" to 2" |
| 3/4" board | 1-1/2" | 2" to 2-1/2" |
| 1-1/2" (2x lumber) | 2-1/2" | 3" to 3-1/2" |
| Face frame to cabinet box | 1-1/4" | 1-5/8" to 2" |
Head Types Explained
- Flat head (countersunk): Sits flush with or below the surface. Use for furniture, cabinets, and any application where a flush finish is needed.
- Pan head: Low rounded head that sits proud of the surface. Use where flush finish is not required — hinges, hardware, electrical boxes.
- Oval head: Partially countersunk with a decorative dome above. Used for visible fastening on trim and hardware.
- Bugle head: Self-countersinks without a washer. Standard for drywall and decking.
- Washer head: Large bearing surface distributes load. Use for cabinet face frames and applications needing high clamping force.
Drive Types: Which to Use
- Star / Torx (T20, T25): Best overall. No cam-out under load. Use for decking, framing, structural work.
- Square (Robertson): Standard in Canada. Excellent cam-out resistance. T-handle drivers are common on job sites.
- Phillips: Most common but prone to cam-out. Fine for light work, problematic for driving long screws.
- Slotted: Avoid for power driving. Only for hand work on very light applications.
Wood Screw Sizes for Common Projects
The fastest way to pick a screw: match the project. The rule of thumb — the screw should penetrate the receiving piece by at least twice the thickness of the piece being fastened.
| Project | Recommended Size | Notes |
|---|---|---|
| Cabinet hinges | #6 × 5/8" – 3/4" | Match existing hinge holes |
| 3/4" stock joinery | #8 × 1-1/4" | The all-purpose workshop screw |
| Shelving into studs | #8 – #10 × 2-1/2" | Must reach 1"+ into the stud |
| Door hinges (into stud) | #9 – #10 × 2-1/2" | Replace one short screw per hinge minimum |
| Deck boards | #10 × 2-1/2" – 3" | Coated exterior screws only — see deck screw guide |
| 2x lumber framing | #10 – #12 × 3" – 3-1/2" | Or structural screws for load-bearing joints |
Where to Buy
Canada:
United States:
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Frequently Asked Questions
What size wood screw do I need?
For most woodworking use #8 screws - they are the most versatile size. For light work like trim and small boxes use #6. For heavy structural work use #10 or #12. The screw should penetrate at least two-thirds of its total length into the receiving piece - for 3/4 inch material that means a 2 inch screw minimum.
Do I need a pilot hole for wood screws?
Always pilot drill in hardwood and near edges in any wood. In hardwood like oak or maple skip the pilot hole and the wood will split. In softwood pilot drill within 1 inch of any edge and for screws #10 and larger. Small screws #6 and under in the middle of softwood panels generally do not need a pilot hole.
What is the difference between a pilot hole and a clearance hole?
A pilot hole is drilled in the receiving piece and is smaller than the screw thread so threads grip the wood. A clearance hole is drilled in the top piece and is larger than the screw shank so the screw slides through freely. Without a clearance hole the screw lifts the top piece instead of clamping the two pieces together.
What drive type is best for wood screws?
Star or Torx drive is the best choice for any application with torque - deck screws, structural work, cabinet assembly. It eliminates cam-out under load. Square Robertson drive is excellent and standard in Canada. Phillips is the most common but strips easily under high torque. Avoid slotted drive for power driving.
What wood screw gauge should I use for cabinets?
Use #8 washer-head screws with T20 star drive for cabinet face frame assembly. Fine thread grips dense hardwood better than coarse thread. Length should be 2 to 2-1/2 inches for standard 3/4 inch cabinet material. Always pilot drill hardwood face frames to prevent splitting.
Related Guides
- Deck Screws Complete Guide — Outdoor screw selection
- Screw Coating Guide — Which coating for outdoor use
- Structural Screws vs Lag Bolts — For framing connections
- Pilot Hole Size Chart for Screws — Every gauge, every material
- Screw Size Selector — Get your exact screw spec instantly
- Nail Size Chart: Penny Sizing Explained — Common vs sinker vs box nail diameters, and the real IRC requirements
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Thomas Leroy
Contractor and founder of BuildToolHQ. 15+ years working with concrete, masonry, and structural fastening on residential and commercial job sites across North America. I built this site to give tradespeople and serious DIYers the same technical knowledge professionals use every day.
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