GSM explained: choosing paper weight

GSM stands for grams per square metre — it's a measure of paper weight, and it's the single spec that changes how a printed piece actually feels in your hand. Higher isn't always better; it depends what you're printing.

Common GSM ranges

70–80 GSM — standard photocopy/document paper. Fine for internal drafts, not ideal for anything double-sided since ink can show through.
90–100 GSM — the sweet spot for thesis bodies, reports and resumes. Heavy enough to prevent show-through, still slim enough for a 200-page document.
120–170 GSM — certificates, flyers and single-sheet marketing pieces that need to feel substantial.
250–300 GSM — covers, business cards and postcards, where rigidity matters more than page count.

Why show-through happens

Show-through is ink from one side becoming visible on the other — it's a function of paper weight and opacity, not just how much ink is used. Colour printing on light paper makes this worse, since colour toner lays down more ink than black and white.

Rule of thumb: if you're printing double-sided in colour, go up one GSM tier from what you'd use for single-sided black and white.

How GSM interacts with binding

Heavier paper adds up fast in a bound document — a 300-page thesis at 100 GSM is noticeably thicker (and heavier to ship) than the same page count at 80 GSM. If your university doesn't specify a GSM, 90–100 is the safe default for body pages, with a heavier cover stock regardless.

Choosing GSM when you order

Every product page shows the GSM options available for that item, with a short note on what each is best suited for. If you're unsure, the price calculator shows how GSM choice affects both price and estimated weight.