Roofing Nail Size: Choosing the Right Length
The nail has to get through the shingles and bite far enough into the deck. That makes length a small sum, not a guess.
Minimum nail length
The rule
The International Residential Code requires asphalt shingle fasteners to be galvanized steel, stainless steel, aluminum or copper roofing nails with at least a 12-gauge (0.105 in) shank and a 3/8 in head, and to penetrate through the sheathing or at least 3/4 in into it. Some manufacturers also ask for the point to show at least 1/8 in below a thin deck, which the calculator includes. Many roofers treat 1-1/4" as the practical minimum on new roofs; the shingle wrapper lists the manufacturer's own minimum, which you should follow.
Typical sizes
| Job | Typical nail length |
|---|---|
| New 3-tab or architectural shingles on 7/16 or 1/2 in deck | 1-1/4 in |
| Thick designer shingles, or 5/8 to 3/4 in deck | 1-1/4 to 1-1/2 in |
| Overlay on one existing layer (where allowed) | 1-3/4 in |
| Hip and ridge cap | 1-3/4 to 2 in (cap is thicker) |
| Felt underlayment | Plastic cap nails, 1 in |
| Synthetic underlayment | Cap nails per manufacturer, often 1 in |
| Wood shakes | 2 in or longer, stainless or hot-dipped galvanized |
Worked examples
Signs the nails are wrong
- Points not showing in the attic on a thin deck: likely too short.
- Points poking far through into the attic: harmless to the roof, but a hazard in finished attics. Use the shortest nail that meets the rule.
- Nails driven crooked or overdriven through the mat lose most of their holding power, whatever their length.
Frequently asked questions
What size nails do you use for shingles?
1-1/4 inch roofing nails are the most common for new shingle roofs on 7/16 or 1/2 inch decks. Use longer nails for thick shingles, overlays and ridge cap.
Can I use 1 inch roofing nails?
Only if they meet the penetration rule and the shingle maker allows it. In practice most shingle installs use 1-1/4 inch or longer.
What length nail for ridge cap?
Usually 1-3/4 to 2 inches, because cap shingles are thicker and fold over the ridge, often over a ridge vent.
Do roofing nails need to go through the plywood?
They must go through the sheathing or at least 3/4 inch into it, whichever comes first. On typical 7/16 or 1/2 inch decks that means through.
Last reviewed 2026-10-10. Results are estimates for planning; confirm quantities with your supplier and requirements with your local building code and the manufacturer's instructions.