GSM tells you how much one square meter of paper weighs, and it directly controls stiffness, cost and fold quality. In our Dongguan facility, we match GSM to box type: 150 g–200 g for light liners, 250 g–300 g for folding cartons, and 350 g+ or board lamination for rigid boxes.
GSM is one of the first numbers buyers see on a packaging quote, but many do not know what it actually controls. This guide explains GSM in practical terms and shows the weight ranges we recommend for real packaging jobs.
What GSM means
GSM stands for grams per square meter. If a sheet of paper measures exactly one meter by one meter and weighs 300 grams, its GSM is 300. The number combines fiber density and caliper into a single manufacturing specification.
Higher GSM usually means thicker, stiffer paper, but not always. Two papers with the same GSM can have different bulk depending on fiber type, pressing and coating. That is why we always pair GSM with micrometer thickness when buyers ask for samples.
Why GSM matters for packaging
GSM affects three things that buyers care about:
- Stiffness — higher GSM resists bending and crushing.
- Print behavior — thicker paper absorbs less moisture and holds ink differently.
- Cost — heavier paper uses more raw material per box.
Specifying the wrong GSM can make a box feel flimsy or make it too rigid to fold cleanly. We correct both mistakes regularly.
Recommended GSM ranges by box type
| Box type | Recommended GSM | Why this range |
|---|---|---|
| Tuck-end folding carton | 250 g–300 g | Stiff enough to stand, thin enough to fold |
| Drawer box sleeve | 300 g–350 g | Holds shape during repeated sliding |
| Rigid box face paper | 128 g–157 g | Thin face paper wraps cleanly around grey board |
| E-commerce mailer | 250 g–350 g kraft | Balance of burst strength and foldability |
| Shopping bag | 200 g–300 g | Carries moderate load without tearing |
| Hang tag | 300 g–400 g | Feels substantial in the hand |
| Gift box insert | 300 g–450 g | Holds product without collapsing |
Real example: from 250 g to 300 g
A cosmetics brand ordered folding cartons at 250 gsm to save cost. After shipping a trial batch, they reported corner crushing during air freight. We increased the GSM to 300 g and added a subtle micro-flute lining. The unit cost rose by 6%, but damage returns fell by 34%. For a high-margin product, the change paid for itself in one season.
GSM is not the same as thickness
This is the most common misunderstanding we see. A 300 gsm uncoated kraft paper may measure 400 microns, while a 300 gsm coated art paper may measure only 320 microns because the coating compresses the sheet. The art paper feels thinner but can be stiffer.
When we sample materials for buyers, we provide:
- GSM
- Micrometer reading in μm
- Bulk value (thickness ÷ GSM)
This trio gives a complete picture of how the paper will behave in die-cutting, folding and use.
How GSM affects printing
| GSM range | Print behavior | Common finishing |
|---|---|---|
| 128 g–200 g | Lightweight, good for fine detail | Lamination, spot UV possible |
| 250 g–300 g | Standard carton weight, balanced ink holdout | Foil, emboss, matte or gloss lamination |
| 350 g+ | Heavy, can stress creases if not scored correctly | Best with deeper creasing matrix |
Uncoated kraft above 350 gsm can crack along fold lines if the creasing width is too narrow. Our die-cut team adjusts the creasing matrix to the exact GSM to prevent burst edges.
Low GSM: when lighter is better
Lower GSM is not a mistake if the structure does not need heavy support. We recommend lower GSM for:
- Inner liners that are not load-bearing
- Lightweight products under 200 g
- Large-format pieces where weight drives freight cost
- Sleeve wraps over rigid boxes
A tea brand we work with uses 157 gsm art paper for an outer sleeve over a rigid box. The sleeve carries the graphics; the 2 mm grey board underneath carries the structure. This split keeps the package light without sacrificing protection.
High GSM: when to go thick
Higher GSM makes sense when:
- The product is heavy or fragile
- The box is the primary protection
- The unboxing experience requires a substantial feel
- The box will be re-used or displayed
Jewelry boxes often use 350 gsm kraft or art paper laminated to 1.5 mm–2 mm grey board. The combination creates a box that feels premium and protects small, high-value items.
GSM and cost
Raw paper is sold by weight. A 350 gsm sheet uses roughly 40% more fiber than a 250 gsm sheet of the same size. That difference flows directly into material cost. However, the total box cost also depends on:
- Sheet size and nesting efficiency on the press sheet
- Waste from die-cutting
- Lamination and finishing steps
Sometimes a lower GSM with a more efficient layout costs less overall than a heavier sheet with poor nesting. Our prepress team optimizes layouts before quoting.
How to specify GSM on your brief
Give your supplier three pieces of information:
- Target GSM range — for example, 300 gsm ± 10 gsm.
- Substrate type — coated art paper, uncoated kraft, or specialty paper.
- Required caliper — if thickness matters for fit or feel.
If you are unsure, ask for a sample card with three GSM options. Feeling the difference is faster than debating numbers.
For more on how paper choice connects to your total quote, read Packaging Cost Breakdown: Where Your Money Actually Goes.
Mistakes to avoid
- Asking for “the thickest paper” without a reason. Excess GSM adds cost and can crack folds.
- Comparing GSM across different paper types. 300 gsm kraft behaves differently from 300 gsm art paper.
- Ignoring caliper. Two 300 gsm papers can have very different thicknesses.
Conclusion
GSM is a simple number with big consequences. The right weight gives your packaging the stiffness, feel and fold quality it needs without wasting material. Use the ranges in this guide as a starting point, then confirm with physical samples. In our Dongguan facility, we are happy to mail a GSM sample card so you can decide with confidence.