If you've ever bought cardstock and wondered what "250gsm" actually means — or why one 300gsm card feels sturdier than another — this guide is for you. After 20 years supplying card to crafters and stationers, we've distilled everything you need to pick the right weight first time, whatever you're making.

What GSM actually means

GSM stands for "grams per square metre" — the weight of a single sheet measured at one square metre in size. It's the standard measure of how heavy, and generally how thick and sturdy, a paper or card is. Higher GSM means a heavier, stiffer sheet; lower GSM means a lighter, more flexible one. As a rough rule of thumb: anything under about 150gsm is usually called paper, and anything above is card — though the line is blurry, and finish and fibre affect how thick a given weight feels.

One important caveat: GSM measures weight, not thickness directly. A textured or bulky card can feel thicker than a smooth card of the same GSM, because the surface adds loft. That's why a 250gsm linen card and a 250gsm smooth card can feel quite different in the hand.

A quick GSM guide by use

• 80–120gsm — everyday printer paper and lightweight craft paper. Good for inserts, liners, layering and origami. Too flimsy for a standalone card.
• 120–170gsm — heavier paper and light card. Ideal for invitation liners, layered elements and backing sheets.
• 200–250gsm — the card-making sweet spot. Sturdy enough for greeting cards and invitations that stand on their own, while still folding cleanly. Our Silkweave linen card is 250gsm for exactly this reason.
• 250–300gsm — premium, substantial card for luxury invitations and keepsake cards. Our pearlescent card is 300gsm.
• 300gsm+ — heavyweight card for standalone signage, box-making and structural craft. Can be harder to fold cleanly without scoring.

How finish changes the feel

Weight isn't the whole story. A linen or textured finish adds surface depth and a tactile, premium quality that a smooth card of the same GSM won't have. A pearlescent coating adds shimmer and a little rigidity. When you're choosing, think about both the weight (for sturdiness) and the finish (for look and feel).

Our simple recommendation

For most card making and invitations, 250gsm is the reliable all-rounder — sturdy, foldable and professional. Step up to 300gsm when you want extra luxury or a card that stands alone without support. Drop to 120–150gsm papers for anything you're layering or using as a liner.

Frequently asked questions

Is higher GSM always better?

Not necessarily — it depends on the job. 250gsm is ideal for most cards and invitations; very high GSM can be hard to fold and is overkill for layered or lightweight elements.

What's the difference between paper and card?

It's roughly a weight distinction: under about 150gsm is usually paper, above is card. Finish and fibre blur the line.

Does GSM measure thickness?

No — it measures weight per square metre. Textured or bulky sheets can feel thicker than smooth sheets of the same GSM.

What GSM is best for wedding invitations?

Typically 250–300gsm for a substantial, quality feel. See our wedding cardstock guide for detail.

Ready to choose your card? Explore our White and Ivory Silkweave linen card, or browse the full A4 card range.