Nail Penny Size (d) to Inches Converter

Pick a penny size (6d, 8d, 16d…) and get the nail length in inches and millimeters plus its typical use — or enter a length to find the nearest penny size.

How It Works

Penny size (d, from the Roman denarius) once priced 100 nails in pennies — today it is pure length code: 6d is 2 in, 8d is 2-1/2 in, 10d is 3 in, 16d is 3-1/2 in. The scale is not linear (16d jumps the pattern), so always convert rather than guess. Box and sinker variants share penny lengths with thinner shanks.

Reference values only — always confirm critical fastening decisions against your engineering specification or the fastener manufacturer.

Keep Reading

• Common Nail
• Framing Nail
• Types of Nails and Their Uses (with Pictures)