A nail size chart translates the traditional penny (d) designation into actual lengths in inches and millimeters, wire gauge, and shank diameter. The penny system dates to 18th-century England, where the price of 100 nails indicated their size — today it remains the universal shorthand used by builders, carpenters, and hardware stores throughout North America. This chart covers all 15 common penny sizes plus a nail type guide and project recommendation helper.
Penny to Inch Conversion Chart
| Penny (d) | Length | Diameter | Common Use |
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Nail Types Guide
How to Use the Nail Size Chart
This nail size chart converts the traditional penny (d) nail designation into actual measurements — length in inches or millimeters, wire gauge, and shank diameter — and provides guidance on choosing the right nail for the job. Whether you're framing walls, hanging trim, or roofing, the right nail size makes a significant difference in both code compliance and structural performance.
Step 1: Search or Browse the Chart
Type a penny size (e.g., 16d), a fractional length (e.g., 3-1/2), a metric length (e.g., 89mm), or a use keyword (e.g., framing) into the search box. The table filters in real time to show only matching rows. To browse the full chart, clear the search field.
Step 2: Toggle Between Inches and Millimeters
Use the in / mm toggle above the chart to switch length and diameter columns between imperial and metric units. The inch display uses traditional fractional notation (e.g., 3-1/2") as used on nail boxes and blueprints. The millimeter display shows decimal mm values for working with metric drawings or international building standards.
Step 3: Use the Project Recommender
Not sure which penny size to reach for? Click a project type in the Which Nail Do I Need? panel — wall framing, decking, trim, roofing, and more. The tool recommends the standard nail size used by professional carpenters for that application, along with a brief explanation. The recommendation highlights the matching row in the chart above so you can see all the specifications at once.
Understanding Wire Gauge and Diameter
Nail wire gauge follows the US wire gauge standard, where a lower gauge number means a thicker shank. A 16d common nail is gauge 8 (0.162" diameter), while a 2d nail is gauge 15 (0.072"). Thicker nails provide more shear strength for structural connections but are more likely to split wood near edges. For trim and finish work near wood edges, choose a smaller gauge (finish nail or brad) to minimize splitting risk.
Choosing the Right Nail Type
The penny size tells you how long a nail is, but the nail type determines its holding power and best application. Common nails have a thick shank for maximum strength in framing. Box nails are thinner to reduce splitting. Sinker nails are vinyl-coated for easier driving with a nail gun. Ring-shank and spiral-shank nails have dramatically higher withdrawal resistance — essential for decking and subfloors where the wood will cycle through moisture changes. Finish and brad nails have small heads that can be set below the surface for trim work.
Frequently Asked Questions
Is this nail size chart free to use?
Yes, this nail size chart is completely free. It runs entirely in your browser — no account required, no data sent to any server. Bookmark it for quick shop or jobsite reference.
Is my data private when using this tool?
Yes, all lookups happen locally in your browser. No information is transmitted to any server. The tool works offline once the page has loaded.
What does the 'd' in nail sizes like 16d stand for?
The 'd' stands for penny — an old English unit dating back to when the price of 100 nails determined the size designation. A 16d nail cost 16 pennies per hundred. Today 'penny' is just a size designation with no relation to price, but the system is still universally used in North American construction.
What is the most common nail size for framing?
16d (3-1/2") sinker nails or common nails are the standard for wall framing in residential construction. They provide enough length to penetrate through 1-1/2" lumber and 1-1/4" into the stud, meeting minimum code requirements for shear strength. 10d and 8d nails are used for lighter framing applications.
What is the difference between common nails and box nails?
Common nails have a thicker shank (larger wire gauge number means thinner wire — lower number means thicker) and a full round flat head. Box nails have a thinner shank of the same length, which reduces the risk of splitting wood but provides slightly less holding power. Box nails are preferred for siding, sheathing, and applications near the edge of boards.
What nail type should I use for decking?
Ring-shank nails (also called annular ring nails) are the best choice for decking. The rings along the shank grip the wood fibers and resist backing out as the wood expands and contracts with moisture changes. Hot-dipped galvanized or stainless steel ring-shank nails are recommended for exterior use to prevent rust staining on the decking surface.
How do I choose the right nail length for a project?
A general rule is that the nail should penetrate at least 2/3 of its total length into the base (receiving) material. For face-nailing two pieces of lumber, choose a nail long enough to pass through the first piece and penetrate at least 1-1/2" into the second. For toenailing, use 10d or 8d nails at a 45-degree angle for a secure connection.
What is the difference between a sinker nail and a common nail?
Sinker nails are vinyl-coated or cement-coated to reduce driving friction and help the nail 'sink' into the wood more easily with a nail gun or hammer. They typically have a slightly smaller head than common nails and a slight taper below the head. Common nails are uncoated with a full flat head. Both are used for framing, but sinkers are more common with pneumatic nail guns.