Paper Weight (gsm) Explained
GSM means grams per square metre. A sheet of paper weighs its area in square metres multiplied by its gsm, so an A4 sheet at 80 gsm weighs 4.99 g.
| Paper size | 80 gsm | 100 gsm | 120 gsm |
|---|---|---|---|
| A4 | 4.99 g | 6.24 g | 7.48 g |
| A3 | 9.98 g | 12.47 g | 14.97 g |
| A5 | 2.49 g | 3.11 g | 3.73 g |
| Letter | 4.83 g | 6.03 g | 7.24 g |
| Paper weight | Typical use |
|---|---|
| 70–80 gsm | Everyday printing and copying |
| 90–100 gsm | Better-quality documents and double-sided printing |
| 120–160 gsm | Brochures, flyers and covers |
| 200 gsm and above | Cards and heavy stock |
How gsm works
GSM stands for grams per square metre. It measures how heavy a sheet would be if it covered one square metre, so it describes the paper itself, not the size of the sheet. To find the weight of one sheet, multiply its area in square metres by the gsm. An A4 sheet has an area of 0.06237 m², so at 80 gsm it weighs 0.06237 × 80 = 4.99 g.
Weight of a ream
A ream is 500 sheets. A ream of A4 at 80 gsm weighs about 2.49 kg, and a box of five reams about 12.5 kg. Heavier gsm means thicker, stiffer paper that also feels more premium and shows less print-through on double-sided pages.
Choosing a weight
For everyday documents 70–80 gsm is normal. Use 100 gsm or more for documents you want to feel substantial, and 120–160 gsm for flyers and brochures. Check that your printer supports the thickness: many home printers handle up to about 160 gsm in the main tray, but this varies by model.
Frequently asked questions
How much does one sheet of A4 paper weigh?
At 80 gsm, one sheet of A4 weighs 4.99 g. At 100 gsm it weighs 6.24 g.
Is gsm the same as thickness?
No. Gsm measures weight per area. Two papers with the same gsm can have different thickness depending on how dense the paper is.
Related
- A4 Paper Size210 × 297 mm
- A3 Paper Size297 × 420 mm
- Letter Paper Size8.5 × 11 in
- Paper Size Converter: mm, Inches and PixelsAny size, any PPI
Last updated: 2026-10-03