In the office, in shipping or in print, knowing how much paper weighs saves postage and prevents overloaded envelopes. The easiest way is the Paper Weight Calculator (Grammage), which turns grammage and sheet area straight into a weight. This guide shows how the calculation works and how to use it day to day.
The formula: grammage times area
Paper is measured in grams per square metre (gsm), known as grammage. The weight of a single sheet is simply sheet weight = grammage (g/m2) × sheet area (m2). For a whole stack, multiply the sheet weight by the number of sheets. You get the sheet area from width times height in metres.
Example: one A4 sheet at 80 gsm
An A4 sheet measures 0.210 m × 0.297 m, giving about 0.06237 m2. At standard copier paper of 80 gsm, one sheet weighs roughly 0.06237 × 80 ≈ 4.99 g. A full ream of 500 sheets therefore comes to about 2.49 kg. That makes it easy to estimate how heavy an envelope will be before you send it.
Putting grammage in context: from copier paper to card
Typical values help you judge quickly: copier paper is around 80 gsm, better-quality letter paper about 90 to 100 gsm, and sturdy card sits between 200 and 300 gsm. The higher the grammage, the heavier and stiffer the sheet, and the sooner a mailing tips into a more expensive postage band.
What it means for postage
For letter post the total weight of the item counts. In Germany a standard letter is allowed up to 20 g and a compact letter up to 50 g. Remember to include the envelope and any enclosures, not just the sheets. Three A4 pages at 80 gsm weigh about 15 g, plus an envelope of roughly 5 to 8 g, and the 20 g limit can get tight. Use the calculator to check this in advance and pick the right postage tier before the item goes in the postbox.
