What size is a sheet of Baltic birch plywood?

Two formats cover most of the trade: 5 x 5 ft and 4 x 8 ft, quoted as 60 by 60 and 48 by 96 inches. In millimetres those are 1525 x 1525 and 1220 x 2440 for Baltic and US panels, which measure 60.039 x 60.039 and 48.031 x 96.063 inches — a shade over the nominal, never under. European mills press 1250 x 2500 and also call it 4x8, so the millimetres are worth stating on an order.

Is 4x8 Baltic birch plywood really 4 feet by 8 feet?

It is sold and ordered as 48 x 96 inches, and that is the size to specify. Measured, it comes out fractionally larger: 1220 x 2440 mm is 48.031 x 96.063 inches, about 0.8 mm over 4 ft on the width and 1.6 mm over 8 ft on the length. The mills round the metric dimension up so the panel is never short of the nominal, so the difference only matters when the sheet must fit an opening cut to exactly 48 inches.

Why is Baltic birch plywood 5x5 instead of 4x8?

Because 1525 x 1525 mm is the format the Baltic birch industry is built around, and it is what the presses and the peeling line are sized for. A square panel also yields better on the parts most shops buy birch for: drawer sides, small case parts and CNC nests, where a long panel wastes more than it saves.

How many square feet is a 5x5 sheet of plywood?

A 1525 x 1525 mm panel is 2.3256 square metres, which is 25.03 square feet. A 1220 x 2440 mm panel is 2.9768 square metres, or 32.04 square feet.

What is the difference between 1220x2440 and 1250x2500 plywood?

Both are sold as 4x8. The Baltic and US sheet is 1220 x 2440 mm, or 48.03 x 96.06 inches; the European one is 1250 x 2500 mm, or 49.21 x 98.43 inches. That is 30 mm wider and 60 mm longer — over an inch and over two inches. A cut list or a nest drawn for one will not run on the other.

What tolerance applies to plywood thickness?

Thickness is the dimension that varies most, and the allowance grows with the panel: a thicker panel is permitted a wider band than a thin one, and sanded panels are held tighter than unsanded. The figure that governs your delivery is the one written into your purchase contract, not the one in a published standard, so state it when you order.

Do I need to allow for panel thickness variation when cutting joinery?

Yes. Set dados and rebates from the panel in front of you rather than from the nominal thickness, and cut a test piece from the same pack. Panels from one pack run close to each other; panels from different production runs need re-checking.

Are plywood panels square?

Squareness and edge straightness both carry tolerances, and both matter more on a CNC than on a table saw, because the machine trusts the edge it registers against. Measure both diagonals before nesting a full sheet; if they differ, trim a reference edge first.

Plywood Sizes & Tolerances

What each format is called, what it actually measures, the three different sheets the trade calls 4x8, and what varies once the pack is opened.

01 — The formats

Ordered by the nominal, made to the millimetre

The trade quotes 5x5, 4x8 and 5x10 — 60 by 60, 48 by 96 and 60 by 120 inches. That is what goes on a purchase order. The millimetre size underneath it varies by where the panel was pressed, and more than most people expect.

Baltic and US sizes are set a shade above the nominal so a panel is never short of the size it is sold as. The European ones are not: 1250 × 2500 runs 31 mm over on the width, and 1500 × 3000 runs 24 mm under.

Baltic birch plywood panel formats: nominal and actual size in millimetres and inches
Sold as	Made in	Millimetres	Actual, inches	vs nominal	m²	ft²
5 x 5 ft60 × 60" nominal	Baltic & USstocked	1525 × 1525	60.039" × 60.039"	+1.0 / +1.0 mm	2.3256	25.03
4 x 8 ft48 × 96" nominal	Baltic & USstocked	1220 × 2440	48.031" × 96.063"	+0.8 / +1.6 mm	2.9768	32.04
— same nominal	Europe	1250 × 2500	49.213" × 98.425"	+30.8 / +61.6 mm	3.1250	33.64
5 x 10 ft60 × 120" nominal	Baltic & US	1525 × 3050	60.039" × 120.079"	+1.0 / +2.0 mm	4.6512	50.07
— same nominal	Europe	1500 × 3000	59.055" × 118.110"	-24.0 / -48.0 mm	4.5000	48.44

Order by the nominal, but state the millimetres. The actual figure matters when the panel has to drop into an opening built to the nominal — and it matters a great deal when a quote could be either the Baltic sheet or the European one. Inches are the millimetre size ÷ 25.4, to three places. We stock the two marked above; the rest are made to order. See also the thickness guide and grade standards.

02 — The expensive confusion

Two different sheets get called 4x8

This is the one that costs money. Both turn up in quotations described as four by eight, and they are 30 mm and 60 mm apart.

Baltic & US — what we supply

1220 × 2440

48.03" × 96.06"

Built to the imperial nominal and marginally over it. Drops onto a cut list drawn in inches.

Europe — over an inch larger

1250 × 2500

49.21" × 98.43"

The European standard sheet. 1.2" wider and 2.4" longer, so it will not fit a rack, a jig or a nest built for the other one.

Specify the millimetres, not the nickname. An order that says 1220 × 2440 cannot be filled with a 1250 × 2500 panel. One that says “4x8” can be, and the argument afterwards is unwinnable. The same applies at 5x10, where the European sheet goes the other way and arrives 25 mm narrower.

03 — Against the American panel

Why this feels backwards

American domestic hardwood plywood is cut to the imperial size exactly: a 4x8 sheet measures 48 by 96 inches, which is 1219.2 by 2438.4 mm. Nothing is added and nothing is taken away.

Construction sheathing goes the other way. APA-rated panels are commonly produced sized for spacing at 477⁄8 by 957⁄8 inches — an eighth under nominal in each direction, so a sheathed wall has an expansion gap built into every joint.

So a US shop meets three conventions: hardwood plywood exactly on nominal, sheathing an eighth under, and Baltic birch a hair over. Only one of the three is a surprise, and it is the one where the surplus is on your side.

04 — Where the surplus goes

A millimetre is not free

On a panel saw the surplus becomes a sliver of offcut and nobody notices. On a CNC it lands on the far corner: register a nest drawn to 1220 × 2440 off two edges and any part hard against that corner is cut partly in air.

Shops solve it by trimming two reference edges before nesting, or by drawing the nest 3–4 mm inside the sheet. Same class of problem as 18 mm not being three quarters of an inch: predictable, and only expensive unmentioned.

05 — Tolerances

What varies, and which number actually binds

Five properties of a panel carry a tolerance: thickness, length and width, squareness, edge straightness, and flatness. In Europe these are set by EN 315, the dimensional tolerance standard for plywood, and mills normally work inside it rather than at its limit.

But the published standard is not what governs your delivery. The tolerance that binds is the one written into the purchase contract. A standard sets an outer boundary broad enough to cover everything from the cheapest panel to the best; a contract sets what you are actually buying. If a dimension matters to your process, put a figure on it in the order.

Thickness: Varies most, and the allowance widens as the panel gets thicker. Sanded panels are held tighter than unsanded, because the calibrating sander is what sets the final figure.
Length & width: Tight in practice — panels are trimmed on a saw line after pressing. Different formats carry different allowances, so a long panel is permitted more drift than a square one.
Squareness: Measured as the difference between the two diagonals. Matters most where a machine registers off an edge and assumes the opposite one is parallel.
Edge straightness: A bowed edge on a full sheet is invisible by eye and immediately obvious to a fence. Worth checking on the reference edge only, since that is the one that propagates.
Flatness: The property least determined by the mill. How the pack was stored, whether it was banded flat, and what the humidity did in transit matter more than what left the press.
What to actually do: Measure the panel in front of you, cut a test piece from the same pack, and re-check when a new production run arrives. Panels within one pack track each other closely; packs from different runs do not.

No table of limit values here on purpose: the standard is not published free, the second-hand versions on supplier sites disagree with each other, and a page about tolerances is the worst place to pass on an unchecked number. Ask us and we will send what the mill states for the panel you are quoting.

06 — Questions

Sizes, asked plainly

What size is a sheet of Baltic birch plywood?: Two formats cover most of the trade: 5 x 5 ft and 4 x 8 ft, quoted as 60 by 60 and 48 by 96 inches. In millimetres those are 1525 x 1525 and 1220 x 2440 for Baltic and US panels, which measure 60.039 x 60.039 and 48.031 x 96.063 inches — a shade over the nominal, never under. European mills press 1250 x 2500 and also call it 4x8, so the millimetres are worth stating on an order.
Is 4x8 Baltic birch plywood really 4 feet by 8 feet?: It is sold and ordered as 48 x 96 inches, and that is the size to specify. Measured, it comes out fractionally larger: 1220 x 2440 mm is 48.031 x 96.063 inches, about 0.8 mm over 4 ft on the width and 1.6 mm over 8 ft on the length. The mills round the metric dimension up so the panel is never short of the nominal, so the difference only matters when the sheet must fit an opening cut to exactly 48 inches.
Why is Baltic birch plywood 5x5 instead of 4x8?: Because 1525 x 1525 mm is the format the Baltic birch industry is built around, and it is what the presses and the peeling line are sized for. A square panel also yields better on the parts most shops buy birch for: drawer sides, small case parts and CNC nests, where a long panel wastes more than it saves.
How many square feet is a 5x5 sheet of plywood?: A 1525 x 1525 mm panel is 2.3256 square metres, which is 25.03 square feet. A 1220 x 2440 mm panel is 2.9768 square metres, or 32.04 square feet.
What is the difference between 1220x2440 and 1250x2500 plywood?: Both are sold as 4x8. The Baltic and US sheet is 1220 x 2440 mm, or 48.03 x 96.06 inches; the European one is 1250 x 2500 mm, or 49.21 x 98.43 inches. That is 30 mm wider and 60 mm longer — over an inch and over two inches. A cut list or a nest drawn for one will not run on the other.
What tolerance applies to plywood thickness?: Thickness is the dimension that varies most, and the allowance grows with the panel: a thicker panel is permitted a wider band than a thin one, and sanded panels are held tighter than unsanded. The figure that governs your delivery is the one written into your purchase contract, not the one in a published standard, so state it when you order.
Do I need to allow for panel thickness variation when cutting joinery?: Yes. Set dados and rebates from the panel in front of you rather than from the nominal thickness, and cut a test piece from the same pack. Panels from one pack run close to each other; panels from different production runs need re-checking.
Are plywood panels square?: Squareness and edge straightness both carry tolerances, and both matter more on a CNC than on a table saw, because the machine trusts the edge it registers against. Measure both diagonals before nesting a full sheet; if they differ, trim a reference edge first.

07 — Enquiries

Send the dimension, not the nickname

Tell us the format in millimetres and what the panel has to do, and we will confirm what we hold and what the mill specifies for it. If a tolerance matters to your process, say so in the enquiry — it is cheaper to agree it now than to inspect for it later.