⚖️ Comparison · Updated for 2026
GSM (grams per square metre) vs LBS (pounds, basis weight)
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
Quick answer: GSM is a direct weight per area — universal across paper types. US paper 'lbs' depends on the parent sheet size, which differs by paper type. 80 lb text ≈ 118 gsm; 80 lb cover ≈ 216 gsm — same number, very different paper. GSM is unambiguous; US lbs is not.
Decision guide — when to use which
Use GSM (grams per square metre) when…
Europe (universal), Asia (universal), most of the world. ISO standard.
Use LBS (pounds, basis weight) when…
US paper industry, Canadian paper industry. Always needs 'text' / 'cover' / 'bond' / 'index' qualifier.
📊 Side-by-side comparison
| Aspect | GSM (grams per square metre) | LBS (pounds, basis weight) |
|---|---|---|
| Basis | Direct: g per m² | Parent sheet weight per 500 sheets |
| Universal across paper types | Yes | No |
| 80 lb 'text' | ≈ 118 gsm | 80 lb |
| 80 lb 'cover' | ≈ 216 gsm | 80 lb |
| Need qualifier? | No | Always |
Frequently asked
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Why is US paper measurement so confusing?
Historical inheritance. Each paper type evolved its own 'parent sheet' size in the 19th-century US paper industry. 80 lb of book text paper, cover stock, and bond paper all weigh 80 pounds — but the parent sheet sizes differ, so the actual paper density differs. GSM eliminates this entirely.
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What's a typical paper weight in gsm?
Office paper (printing): 80 gsm. Letterhead: 100-120 gsm. Business card: 300-400 gsm. Book pages: 70-100 gsm. Magazine cover: 200-300 gsm.
Reviewed for 2026. All conversion factors and historical references verified against official sources (ISO standards, government weights & measures legislation, IEC technical specifications). Built by a UK-based qualified primary teacher and FA Level 2 coach as part of 247QuickTools' free utility-tools project. We don't sell SEO links or accept paid placements in this content.