What Is GSM in Paper? Paper Weights Explained

Published 18 July 2026

If you have ever bought paper and seen “80gsm” or “300gsm” on the pack and wondered what it means, you are in the right place. GSM is the single most useful number for understanding how a paper will feel and behave. Here is what it means, what the common weights are for, and how it maps to the US “pound” system.

What GSM actually means

GSM stands for grams per square metre (often written g/m²). It is exactly what it sounds like: the weight in grams of a single sheet of that paper cut to one square metre. Because it is measured against a fixed area, GSM is a true, universal measure of paper density — a higher GSM means a heavier, usually thicker and stiffer sheet, regardless of the sheet's actual size.

That last point is why GSM is so useful. An A4 sheet and an A3 sheet of the same paper have the same GSM even though A3 is twice the area and twice the weight. The GSM describes the paper, not the sheet, so you can compare any two papers directly.

Common paper weights and what they feel like

• 35–55gsm — very light. Newspaper, cheap flyers, tracing-thin stock. Shows through easily.
• 70–90gsm — standard copy/printer paper. The 80gsm sheet in most office printers lives here. Fine for everyday documents; some show-through when printing double-sided.
• 90–120gsm — premium office / inkjet paper. Noticeably crisper, less show-through, good for letterheads, résumés and photos on plain paper.
• 120–160gsm — heavy paper / light card. Brochures, posters, quality flyers. Starts to feel substantial and holds a fold well.
• 160–250gsm — cardstock. Greeting cards, invitations, covers, flash cards. Stiff enough to stand up.
• 250–350gsm — heavy cardstock / board. Business cards, postcards, sturdy tags, game cards. 300gsm is a common “nice card” weight.
• 350gsm and up — board. Book covers, packaging, heavy craft. Often needs a printer that can handle thick media.

GSM vs lb (US basis weight)

In the United States, paper is often sold by “pound” (lb) — for example “20 lb bond” or “110 lb cover”. This is the basis weight: the weight in pounds of a ream (500 sheets) of the paper at its uncut basic size. The catch is that the basic size differs by paper type — bond, text, cover and index each use a different reference sheet — so the same “80 lb” can mean very different papers. This is exactly why GSM, which uses one fixed area for everything, is clearer.

Some rough conversions to give you a feel (approximate, because the paper category matters):

• 20 lb bond ≈ 75gsm (standard copy paper)
• 24 lb bond ≈ 90gsm
• 32 lb bond ≈ 120gsm
• 65 lb cover ≈ 176gsm (light cardstock)
• 80 lb cover ≈ 216gsm (cardstock)
• 110 lb index ≈ 200gsm; 110 lb cover ≈ 298gsm

If you only remember one thing: for copy paper, multiply the bond lb number by roughly 3.76 to get GSM (20 lb × 3.76 ≈ 75). For cover stock the multiplier is different, which is the whole problem with the lb system.

Which weight for which job?

• Everyday printing, worksheets, drafts: 80gsm. Cheap and perfectly good.
• Double-sided documents, résumés, letterheads: 90–120gsm to stop show-through and feel professional.
• Flyers, brochures, posters: 120–170gsm.
• Invitations, greeting cards, flash cards, bookmarks: 200–300gsm cardstock.
• Watercolour and heavy art: 300gsm+ specialist paper (watercolour paper is measured in GSM too).
• Board games, playing cards, sturdy tags: 250–350gsm, ideally with a smooth finish.

Does paper weight affect printsheet.io templates?

Not at all — and that is the good news. Every template here is drawn in real millimetres and prints at exact scale on any weight of paper your printer accepts. Choose the GSM that suits the job: light copy paper for a quick worksheet, or heavy cardstock for a game board or flash cards. The layout and measurements stay identical; only the feel changes. Just check your printer's spec for the maximum weight it can feed, especially for anything above about 200gsm. And whatever weight you pick, run the ruler test once to confirm your printer prints at true scale.

Frequently asked questions