BF, GSM & BURSTING STRENGTH

A corrugated box quote usually lists the paper by its GSM and BF, and the box by its bursting strength. These three numbers tell you how strong the box will be. Here is what each one means.

GSM — how heavy the paper is

GSM is grams per square metre: the weight of one square metre of the kraft paper. Heavier paper is thicker and stronger. Common kraft papers range from light papers for inner layers to heavy papers for outer liners.

BF — how strong the paper is for its weight

BF is the bursting factor of the paper: its resistance to bursting, adjusted for its weight. Two papers of the same GSM can have different BF; the higher-BF paper is stronger.

BS — how much pressure the board takes

Bursting strength (BS) is the pressure, in kg/cm², needed to burst the board. For a single paper it works out as BS = BF × GSM ÷ 1000. A box's BS comes from all its liners and flutes together, which is why the paper combination matters as much as the ply.

Two more tests worth asking for

• Compression test — how much load the box takes from above before it buckles; this decides how high you can stack
• Cobb test — how much water the paper absorbs; important for cold storage, humid godowns and export

How we check

Our plant tests BF, BS, GSM, compression and Cobb in-house, and our quality system is certified to ISO 9001:2015. See the testing equipment on our infrastructure and quality policy pages, and read which ply to choose.

How to order

Call or WhatsApp us on +91 99998-11449 with the box size (length × width × height), ply, print and quantity, or the product you need to pack. We reply with a quote, make the boxes at our Faridabad plant and deliver within 24 hours of dispatch being agreed.