How far from the edge should I place screws?

The minimum edge distance for screws is typically 4 times the screw diameter. For a 4mm screw, that is 16mm from the edge. For nails, use 5 times the nail diameter. These distances prevent the wood from splitting along the grain.

How far from the end of a board should the first screw be?

The minimum end distance for screws is typically 10 times the screw diameter (40mm for a 4mm screw). For nails, use 15 times the diameter. End grain is more prone to splitting, hence the greater distance requirement.

Can I reduce spacing by drilling pilot holes?

Pilot holes can reduce the risk of splitting, potentially allowing you to reduce spacing by 20-30%. However, the minimum edge and end distances should still be respected. When in doubt, use the standard spacing recommendations.

WoodCalcs

Fastener Spacing Calculator — Avoid Splitting

Calculate optimal screw or nail spacing to avoid splitting timber. Based on fastener diameter and timber dimensions.

Board Length

Board Width

Board Thickness

Fastener Diameter

Fastener Type

How We Calculate This

This calculator uses standard timber engineering rules for fastener spacing to prevent splitting.

Standard rules

Screws: Edge distance = 4d, End distance = 10d, Spacing = 7d

Nails: Edge distance = 5d, End distance = 15d, Spacing = 10d

Bolts: Edge distance = 4d, End distance = 7d, Spacing = 5d

Where d = fastener diameter in mm.

Frequently Asked Questions

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Last updated: February 2026

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