Quick answer
Corrugated plastic sheet is offered in multiple nominal thicknesses, but thickness does not determine box capacity. Use it only to shortlist samples. Also specify grammage, resin, flute direction, footprint, height, joints, load, stack, temperature, moisture, handling and required life, then test the finished box and pallet under representative conditions.
Corrugated plastic thickness chart: mm, inches, weight and typical uses
Corrugated plastic is extruded, so the same nominal thickness can be produced at different weights by changing the wall (skin) thickness and the rib spacing. The table below shows the ranges that packaging factories actually run, with the sheet weight for a standard 48 × 96 in (1,220 × 2,440 mm) blank at a mid-range grammage.
| Thickness | Inches | Typical grammage (g/m²) | Weight of a 48 × 96 in sheet | Cardboard equivalent | Typical uses |
|---|---|---|---|---|---|
| 2 mm | 0.079 in (≈ 5/64") | 300–450 | 1.1 kg / 2.5 lb (at 380 g/m²) | E-flute | Layer pads, dividers, folder inserts, small die-cut pieces, printed POP |
| 2.5–3 mm | 0.098–0.118 in (≈ 1/8") | 450–650 | 1.6 kg / 3.6 lb (at 550 g/m²) | B-flute | Light totes, archive boxes, mailers, economy sign blanks, protection board |
| 4 mm | 0.157 in (≈ 5/32") | 650–1,000 | 2.2 kg / 4.9 lb (at 750 g/m²) | C-flute | Standard US yard-sign blank; RPC-style produce totes; warehouse and picking totes; floor protection |
| 5 mm | 0.197 in (≈ 3/16") | 900–1,200 | 3.0 kg / 6.6 lb (at 1,000 g/m²) | BC double-wall | Export produce boxes (banana, avocado, grape, vegetables), fish totes, returnable shippers |
| 6 mm | 0.236 in (≈ 1/4") | 1,100–1,500 | 3.9 kg / 8.5 lb (at 1,300 g/m²) | Heavy double-wall | Heavy-duty totes, seafood totes with 30 kg+ payloads, pallet sleeves, large signs |
| 8 mm | 0.315 in (≈ 5/16") | 1,400–2,000 | 5.1 kg / 11.2 lb (at 1,700 g/m²) | Triple-wall | Sleeve-pack bins, automotive dunnage, long-run returnable containers |
| 10 mm | 0.394 in (≈ 3/8") | 1,800–2,500 | 6.3 kg / 13.8 lb (at 2,100 g/m²) | Triple-wall + | Bulk harvest bins (48 × 40 in), heavy pallet sleeves, structural panels |
Sheet weight = grammage × 2.98 m² (the area of a 48 × 96 in sheet). Standard sheet sizes are 48 × 96 in (1,220 × 2,440 mm) and 1,000 × 2,000 mm; extruders can run custom widths up to about 2,400 mm and any cut length, so box blanks are normally cut to size at the factory rather than from standard sheets.
How much weight can a corrugated plastic box hold? Load guide by wall thickness
A box is not a sheet: capacity depends on grammage, resin, rib geometry and direction, footprint, height, joints, load distribution, pallet support, temperature, moisture, handling and stack duration. Treat the rows below as sample-screening hypotheses only; they are not load ratings or life guarantees.
| Wall thickness | Candidate load band | Stack test to define | Life evidence required | Example screening uses |
|---|---|---|---|---|
| 2–2.5 mm | Define from sample | Protective-use or stacking protocol | Trial records and retirement criteria | Inserts, dividers, partitions, small mailers |
| 3 mm | Define from sample | Load, layers, time and environment | Trial records and retirement criteria | Light totes, archive boxes and parts totes |
| 4 mm | Define from sample | Load, layers, time and environment | Trial records and retirement criteria | Produce, warehouse and retail-ready totes |
| 5 mm | Define from sample | Load, layers, cold chain and moisture | Trial records and retirement criteria | Produce, seafood and returnable shippers |
| 6 mm | Define from sample | Load, equipment, moisture and duration | Trial records and retirement criteria | Heavy totes and pallet sleeves |
| 8 mm | Define with pallet/base | Compression, dynamics and handling | Trial records and retirement criteria | Sleeve packs and industrial dunnage |
| 10 mm | Define with pallet/base | Compression, dynamics and handling | Trial records and retirement criteria | Bulk bins and structural sleeves |
Four rules of thumb when sizing wall thickness
- Test cold impact. Screen resin grade, thickness and joints at the lowest expected product and handling temperature.
- Test wet handling. Include ice or water weight, drains, wet grips, forklift contact, compression and pallet stability in the protocol.
- Specify grammage with thickness. Skin and rib geometry vary at the same nominal thickness, so compare sample data and finished-box tests.
- Record flute direction. It affects converting and compression; lock it on the drawing and verify the finished box in the intended orientation.
Sheet specification checklist: what to put on a corrugated plastic RFQ
Buyers who send a full specification get a comparable quote first time. For corrugated polypropylene sheet or box blanks, state:
- Thickness and grammage — e.g. "4 mm, 800 g/m²" — not thickness alone.
- Sheet or blank size and flute direction — e.g. 1,220 × 2,440 mm, flutes running along the 2,440 mm length.
- Color — natural (translucent), white, black or Pantone match; white and colored sheets carry 2–5% masterbatch and cost slightly more than natural.
- Additives and documents — define UV, anti-static or flame performance and intended food contact; request evidence tied to the finished SKU, resin, additives, inks, factory and target market.
- Surface treatment — corona treatment (≥ 38 dyne) if the sheet will be screen or digitally printed; ask for the treatment date because corona fades after a few months.
- Converting — die-cut, creased, printed, ultrasonically welded, riveted or stitched corners; hand holes; lids or drop-fronts.
- Quantity and delivery — pallet or 20 ft / 40 ft container quantities; a 40 ft HQ container holds roughly 2,000–2,400 m² of 4 mm sheet or 8,000–12,000 folded 40 × 30 cm totes.
Sign blanks: which thickness for yard signs, real-estate signs and event boards?
In the United States the standard corrugated plastic sign blank is 4 mm (0.157 in), typically 650–750 g/m² for economy political and real-estate signs and 900–1,000 g/m² for signs that must survive a full season outdoors. 3 mm boards are sold as a lower-cost option but flex in wind above about 24 × 18 in. Larger boards — 24 × 36 in and 36 × 48 in — move to 6 mm or 10 mm with vertical flutes so that H-stakes and grommets do not tear through. See our yard sign size guide for standard sizes and stake spacing.
Produce and seafood boxes: choosing between 4, 5 and 6 mm
For fresh produce and seafood, shortlist thickness and grammage from load and moisture, then test candidate constructions. Include footprint, height, joints, drain or vent pattern, pallet support, stack duration, temperature, water or ice exposure, impact, washing and route handling. Our fish tote sizes guide covers dimensional inputs; the material comparison uses measured cost per successful trip.
| Application | Recommended thickness | Grammage | Notes |
|---|---|---|---|
| Berry / tomato / pepper totes, 40 × 30 cm | 4 mm | 750–850 g/m² | Vented walls, vertical flutes, nestable when empty |
| Banana / avocado / citrus export box, 18–22 kg | 5 mm | 950–1,100 g/m² | Column-stack design, ventilation matched to ripening-room airflow |
| Fish tote candidate | Screen 5 mm | Quote and test grammage | Validate drains, joints, load, washing and SKU-specific documents |
| Fish / meat tote, 60–100 lb | 6 mm | 1,200–1,400 g/m² | Riveted or welded corners, reinforced hand holes |
| Harvest bin, 48 × 40 in, 800–1,200 lb | 8–10 mm sleeve | 1,700–2,200 g/m² | Used with a plastic or wooden pallet base; see the harvest bins cost guide |
| Yard sign blank, 24 × 18 in | 4 mm | 650–1,000 g/m² | UV-stabilised, corona-treated for printing |
How thickness changes the price
Resin weight is an important cost input, but quotations also change with resin grade, color, additives, extrusion setup, converting, print, packing, quantity and freight. Compare candidates on the same specification and date; do not infer life from an extra increment of grammage without finished-box testing.
For U.S. imports, match the finished SKU to the complete product scope, verify actual plant and origin, identify producer and exporter, and confirm classification, value and current entry instructions with a customs broker. See the Philippines sourcing and document workflow.
Frequently asked questions
What thickness of corrugated plastic should I use for a box?
Use thickness only to shortlist samples. Also specify grammage, resin, flute direction, footprint, height, joints, load, stack, temperature, moisture, handling and required life, then test the finished box and pallet.
How thick is a standard yard sign or sign blank?
The standard corrugated plastic sign blank in the US is 4 mm (0.157 in, about 5/32"), usually 650–1,000 g/m². 3 mm blanks are a lower-cost option for small signs, and 6 mm or 10 mm boards are used for 24 × 36 in and larger signs so that stakes and grommets do not tear through.
How much weight can a 4 mm corrugated plastic box hold?
There is no reliable capacity from nominal thickness alone. Test the approved sheet and finished box at representative load, temperature, humidity, pallet pattern, stack time and handling.
What does g/m² (grammage) mean for corrugated plastic, and why does it matter more than thickness?
Grammage is the weight of one square metre of sheet. Because corrugated plastic is extruded, a 4 mm sheet can be made at 600 g/m² with thin skins or at 1,000 g/m² with thick skins; the heavier sheet is around 50% stiffer and far more crush-resistant even though the thickness is identical. Two quotes for "4 mm sheet" are only comparable when the grammage matches.
Is 5 mm or 6 mm better for produce and seafood boxes?
Screen both constructions against the same load, footprint, joints, pallet, stack duration, temperature, moisture, handling and required life, then choose from finished-box test results.
How should a U.S. importer review duties?
Match the finished SKU to the complete product scope and verify classification, actual origin, producer, exporter, value and current entry instructions with a customs broker or adviser.
Need a thickness recommendation for your box?
Send product, load, dimensions, joints, pallet, stack duration, temperature, moisture, handling, required life, quantity, route and required date. The reply will state candidate specifications, sample options and achievable schedule.
Request a specification reviewSee also: Buying corrugated polypropylene sheets in bulk · PP box suppliers outside China and Vietnam