Guides / Specification

Plywood Sizes and Thickness Tolerance from Vietnam

September 21, 2026

Two numbers cause more rejected containers than any other line on a plywood order: the sheet size and the actual thickness. Both look obvious and neither is.

Standard sheet sizes

Size	Where it is used
1220 x 2440 mm	The 4 x 8 ft sheet. United States, Asia, most of the world
1250 x 2500 mm	European standard size
915 x 1830 mm	Small format, common for packing and some furniture parts
1525 x 1525 mm	The square format that follows Russian birch conventions

Anything else is a cut to size order. Mills will do it, and it costs more because the press runs the standard format and the panel is then trimmed, which produces offcuts somebody has to pay for.

If your cutting plan yields better from a non standard size, do the arithmetic before you assume cut to size is expensive. Sometimes it is cheaper than the waste.

Nominal thickness is a name

A panel sold as 18 mm is not promised to be 18 mm. Sanding takes material off, the press varies slightly across the platen, and mills build the panel to a target that leaves room for both.

In practice a nominal 18 mm panel from Vietnam commonly arrives somewhere between 17.2 and 18.0 mm. That is not a defect unless your order said otherwise. It becomes a defect when your CNC program, your groove or your hardware assumed a real 18.

Two ways to handle it:

1. Order to actual thickness. Write “17.8 mm actual, plus or minus 0.3 mm” instead of “18 mm”
2. Design for the range. Tell your shop the panel is nominal and let them measure the first sheet

What tolerance costs

Tolerance is a price line, the same as grade and bond. Holding a sanded panel to plus or minus 0.3 mm means thinner veneers, more of them, longer press cycles and a sorting step that pulls the outliers. Holding plus or minus 1 mm means none of that.

Typical expectations, not promises:

Panel	Typical tolerance
Sanded, calibrated both sides	Around plus or minus 0.3 to 0.5 mm
Sanded standard	Around plus or minus 0.5 to 0.8 mm
Unsanded, packing or formwork	Around plus or minus 0.8 to 1.2 mm

Ask the mill which of those it holds as standard. A mill that answers with a number and a measuring method is a different proposition from one that answers yes.

Length, width and squareness

Thickness gets the attention, and the other three cause the quiet problems:

• Length and width are usually held within a couple of millimetres. Ask, because a short sheet cannot be made longer
• Squareness matters when the panel is cut on a beam saw. Out of square sheets waste the first cut
• Flatness is the one nobody writes down and everybody argues about. It is mostly a storage and moisture question, covered in packing and storing plywood

The line to write

“18 mm nominal, 17.6 mm actual minimum, plus or minus 0.3 mm, 1220 x 2440 mm, squareness within 2 mm on the diagonal, measured at five points per sheet.”

That is one sentence, and it removes the most expensive argument in this trade. The rest of the specification is in what your enquiry has to say.

Frequently asked questions

Keep reading

• Plywood for Speaker Boxes: Stiffness, Damping and Panel Specification
• Rubberwood Plywood from Vietnam: What the Species Brings and Where It Needs Care