Nominal vs actual lumber sizes for pallets

Why pallet specs use actual sizes

Construction lumber is sold by nominal size: a "2x4" is not 2 by 4 in. Pallet stock is different again. Most pallet parts are cut to size as shook from cants or rough lumber, so their thickness and width are whatever the mill saws, not a trade size.

For that reason, the Uniform Standard for Wood Pallets and PDS always specify actual dimensions at manufacture. When a spec says "5/8 x 3-1/2 x 40", those are the real measurements of the part. Nominal names are only shorthand in conversation.

Nominal and actual sizes

Common deckboard thicknesses in pallet specs run 1/2, 9/16, 5/8, 11/16, 3/4 and 7/8 in. Common widths are 3-1/2, 3-3/4, 4, 5-1/2, 5-3/4 and 6 in. Stringer widths run 1-1/8 to 2 in and more, with heights of 3-1/2, 3-3/4, 4 and 5-1/2 in.

Why it matters

The difference changes real numbers:

• Board feet are computed from actual dimensions. A 1-3/8 in stringer has about 8% less wood than a 1-1/2 in one.
• Overall height adds actual thicknesses. The GMA-style 48 x 40 is 5/8 + 3-1/2 + 5/8 = 4.75 in, not 5 in.
• Deck gaps depend on actual widths. Seven boards totaling 28-1/2 in of actual width on a 48 in pallet give 3.25 in gaps.
• Nail length must cover actual deck thickness plus at least 1-1/4 in of penetration into the stringer.
• Capacity depends heavily on actual stringer height and width.

Manufacturing tolerances on actual sizes

The Uniform Standard (2012, Section 5.1.4) allows:

At least 50% of pieces must meet or exceed the target size, and two standard deviations must fall within tolerance. See pallet tolerances.

Fraction, decimal and metric equivalents

PDS spec sheets show decimals (0.625, 1.375), while production orders often use fractions (5/8 x 3-1/2 x 40). Both describe the same actual part. Pick one style per document and keep it consistent across the drawing, parts list and cut list.

How to write sizes on a drawing or RFQ

• Give every part as actual dimensions: thickness x width x length for boards, width x height x length for stringers and blocks.
• Use shop fractions (5/8 in, 1-3/8 in) or decimals (0.625, 1.375), consistently.
• If you use nominal shorthand, add the actual size: "1x6 (3/4 x 5-1/2 in)".
• For metric pallets, give millimeters.

How palletdesign.ai uses actual sizes

palletdesign.ai stores every dimension as an actual size in inches and only changes the display between fractions, decimals and millimeters. Board feet, weight, deck gaps, height and nail counts all come from those actual sizes, so the drawing, parts list and cut list match what the saw produces. See how to read a pallet drawing.