Choose a folding carton board grade by matching the job to the fibre: SBS when you need premium whiteness and a clean print surface, FBB when stiffness-to-weight and shelf presence matter most, CRB / WLC when recycled content and landed cost lead, and CUK when strength and moisture tolerance beat a bright white face. Caliper, folding behaviour, product protection, food-contact route, print cost and lead time all follow from that one decision — so board grade is the first carton spec to settle, not the last.
Foldveil folding cartons are made to order on a paper converting platform with offset, flexo, gravure and digital print, plus finishing such as foil, emboss, soft touch and window patching. Board grade, dieline and carton compression are engineered per project. Like every Foldveil format there is no public price or MOQ list, and any certification or compliance claim is confirmed per factory, material and production run and shared with the quote.
The four board grades at a glance
Most carton briefs land in one of four grade families. The table below is the short version; the sections after it explain the trade-offs.
| Grade | What it is | Face / print | Recycled content | Typical jobs |
|---|---|---|---|---|
| SBS (solid bleached sulfate) | Virgin bleached chemical pulp, usually with a coated top | Brightest white, highest print fidelity | None (virgin) | Cosmetics, premium food, healthcare, gifting |
| FBB (folding boxboard) | Multi-layer virgin board — bleached outer plies over a mechanical middle | Good white face, good print | None (virgin) | Confectionery, cosmetics, pharma, retail cartons |
| CRB / WLC (coated recycled board) | Recycled fibre core with a coated white liner | Serviceable for graphics, generally less bright | High | Dry goods, household, toys, secondary cartons |
| CUK (coated unbleached kraft) | Unbleached chemical pulp with a coated top | Natural kraft look, strong | None (virgin) | Beverage, hardware, industrial, dry and frozen food |
Board grade families and the jobs they suit follow the converter classifications set out in Netpak's paperboard guide and Meyers' grade selection guide. Micro-flute corrugated is a fifth option when a carton needs extra crush resistance, but it converts differently and belongs in a separate conversation.
What the board grade actually controls
Rather than thinking of board as "the white stuff", it is worth knowing the seven things the grade decision fixes:
- Stiffness and caliper — how much the filled carton resists bulging when stacked
- Print quality — how bright the face is and how faithfully it holds fine graphics
- Scoring and folding — whether the board creases cleanly or cracks on the fold line
- Product protection — crush resistance and, on coated grades, some moisture resistance
- Food-contact suitability — which fibre and barrier route is allowed for the end use
- Sustainability claims — recycled content and fibre sourcing you can actually evidence
- Converting cost and lead time — the grade drives material cost, waste and run speed
Because those factors move together, choosing a grade purely on headline price tends to push cost somewhere else — usually into damaged stock or a reprint.
SBS: premium surface and purity
Solid bleached sulfate is the grade buyers reach for when the carton is part of the product experience. Its bright, coated face reproduces fine detail, skin tones and brand colours most faithfully, and its virgin fibre gives a clean, low-odour substrate for sensitive goods. That is why SBS dominates cosmetics, premium food and healthcare cartons.
The trade-off is cost: SBS is the most expensive of the four, and if your artwork is simple or the carton ships inside another box, you are paying for print quality no customer will see.
FBB: the stiffness-to-weight default for retail
Folding boxboard is a multi-layer construction — bleached outer plies around a mechanical pulp middle — which gives it more stiffness per gram than a single-ply board. For a retail carton that has to stand up on a shelf, stack in a case and survive a courier journey without denting, that stiffness-to-weight ratio is often the deciding factor.
FBB is the sensible default for confectionery, cosmetics, pharma and general retail cartons where you want a good white face and solid protection without moving up to SBS prices.
CRB / WLC: recycled content and cost
Coated recycled board — also called white-lined chipboard — puts a coated white liner over a recycled fibre core. It is the grade that lets a carton carry high recycled content and a lower material cost at the same time, which is why it is common on dry goods, household products, toys and secondary cartons.
The compromise is the face: recycled cores are generally less bright and less pure than virgin board, so the finest graphics and the most sensitive food uses are a harder fit. Recycled-content and fibre-sourcing claims also have to be evidenced for the specific material — we cover how to phrase that safely in our guide to sustainability claims without greenwashing.
CUK: strength and moisture tolerance
Coated unbleached kraft uses unbleached chemical pulp, giving a strong, naturally brown board with better wet strength and a warmer, more tactile look. It suits beverage multipacks, hardware and industrial cartons, and dry or frozen food where the natural kraft appearance is part of the brand.
The catch is colour: a kraft face shifts how brand inks read, so print targets should be agreed on the actual board rather than on a white reference.
Caliper, grammage and the numbers that reach your quote
Two numbers describe the board itself, and both show up on a carton quote:
- Caliper — the thickness of the board, measured in microns or mils
- Grammage — the weight per unit area, in gsm
They are not interchangeable, and neither one alone predicts performance: two boards of the same caliper can behave very differently if their layer structure differs. Stiffness — the property that actually keeps a carton from bowing — depends on the fibre, the construction and the caliper together.
That is why we do not quote a "standard" caliper. We set the board around your packed weight, carton dimensions, stacking load and handling route, then confirm it with the quote. If you already have a dieline and a target look, that is enough to start.
Recycled content and food contact: verify before you print
Food-contact compliance is where board grade stops being an aesthetic choice. Recycled fibre is permitted in food-contact paper and board, but only where the specific end use has been assessed and the material is controlled:
- In the US, food-contact substances are governed by FDA rules, and reclaimed fibre for food packaging sits under provisions including 21 CFR 176.260 (see the RPTA comprehensive program and the FDA's food-contact substances overview).
- In Europe, the framework is EU 1935/2004, supported by national recommendations such as the BfR Recommendation XXXVI for paper and board and industry guidance from the paper and board chain (CEPI/CITPA food-contact guidelines).
The practical rule for buyers: never assume a grade is food-safe because it is "paper". The correct route depends on the fibre, any coating or barrier, and the food it touches. Foldveil confirms document scope per factory, material and production run; if your carton is for food, start from our food-contact document pack.
Finishing changes which board you can choose
Finishing and board grade constrain each other. Foil stamping, embossing and soft-touch lamination all sit on the sheet, and a heavily finished carton may need a heavier or more stable board to avoid warping. Window patching needs a board that holds the patch film cleanly. And the print method matters: digital is economical for short runs and versioned artwork, while offset and flexo reward longer runs — our comparison of flexo, digital, gravure and offset walks through that choice.
Tell us the finish early, because it can change the board recommendation more than the artwork does.
Board is half the carton: style, inserts and freight
A carton is a board grade plus a box style plus whatever protects the product inside. Tuck-end, auto-lock-bottom and sleeve styles put different demands on board caliper, and an insert — molded pulp, card or foam — may remove the need for extra board stiffness in the first place. If you are still deciding between a folded carton and a sturdier option, our folding cartons vs rigid boxes comparison covers unit cost and unboxing trade-offs, and molded pulp trays covers when a fibre insert is the better protection.
Two freight points are worth settling at the same time, because they can move the board decision:
- Cartons ship flat, so the container loading math for your carton size is part of the true cost.
- Oversized cartons raise dimensional-weight charges, which we break down in the right-sizing guide. Getting the dieline right is also a freight decision.
See the full folding carton range, or compare with rigid boxes and molded pulp trays if the product needs more structure.
What to send for an accurate carton quote
The more of this you can share, the fewer back-and-forth rounds it takes:
- Packed product dimensions and weight (product plus any insert or inner wrap)
- Carton style, if you have a preference — tuck-end, auto-lock bottom, sleeve or your own dieline
- Board direction: premium print (SBS), retail stiffness (FBB), recycled content and cost (CRB/WLC) or strength and kraft look (CUK)
- Print method and coverage, plus any finishing (foil, emboss, soft touch, window patch)
- Whether the carton touches food, and the target market
- Quantity, and the destination if it changes the compliance route
You do not need every field to start — a dieline plus a quantity is enough for us to come back with a board recommendation and a quote. Open the RFQ form to begin, or send what you have and we will tell you what still matters.