How long should nails be for a nail gun?

The nail must pass fully through the top material and penetrate the substrate by at least 2.5 times the top material thickness for softwood, or 2 times for hardwood. For example, fixing 18mm plywood to softwood requires at least 18mm + 45mm = 63mm nails. Toe nailing and end grain need longer nails due to reduced holding power.

What gauge nail gun do I need?

18-gauge brad nailers are for trim and thin material (up to 12mm). 16-gauge finish nailers handle most joinery and trim up to 25mm. 15-gauge angled nailers are for heavier trim and light structural. 10-12 gauge framing nailers are for structural framing, decking, and sheathing.

Can I nail into end grain?

End grain has roughly 50% of the holding power of face or edge grain. For structural connections into end grain, use ring shank nails, add adhesive, or preferably use screws. Non-structural end grain connections (like skirting boards to studs) work fine with standard nails at increased length.

Toe nailing is driving nails at an angle (typically 30-45 degrees) through one piece into another, used where face nailing is not possible (e.g., studs to sole plate). It requires longer nails than face nailing and typically 3-4 nails per joint for adequate holding. Pre-drilling helps prevent splitting in hardwoods.

WoodCalcs

Nail Gun Selection Calculator — Correct Nail Length & Gauge

Find the right nail length, gauge, and type for your material and connection. Get holding power estimates and nails-per-joint recommendations.

Top Material Thickness

Material thickness

Substrate

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Connection Type

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Load Type

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How We Calculate This

This calculator determines the minimum nail length based on the top material thickness, required substrate penetration, and connection type. It then recommends nail gauge, type, and quantity based on the application.

Minimum penetration ratios

Softwood: 2.5x top material thickness
Hardwood: 2.0x top material thickness
Plywood: 2.5x top material thickness
OSB: 3.0x top material thickness

Connection adjustments

Face nailing: x1.0 (standard)
Toe nailing: x1.3 (angle reduces effective penetration)
End grain: x1.5 (poor withdrawal resistance)

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.