All About Paper Weights And Sizes

We’ve discussed the various types of paper available to purchase, such as photo or recyclable, in previous articles on FMS Blog, however we thought we’d take a closer look at the essential office item itself. Most people will buy this common stationery item and use it without thinking any further, but the world of paper is more interesting than you may realise.

Today is Get Crafty day for National Stationery Week and paper or card is often the material of choice for crafting so we’re taking a closer look at the incredibly versatile product.

Sizing In Paper

In terms of sizes, most of the world adheres to the international standard (ISO) paper sizes that were originally created in the 18th century. The original method of reaching the ISO size was described by the German scientist Georg Christoph Lichtenberg in 1786.

ISO sizing uses the square root of two to achieve the height-to-width ratio. To put this in terms that are perhaps easier to understand, if you place two pieces of A4 paper next to each other along their lengths, they will equal the same size as an A3 sheet. At the same time, if you fold an A4 piece in half along its length, it will equal the size of an A5 sheet.

FMS Blog Paper Sizing

The ISO sizing is also split into A series, B series and C series which all complement each other in turn. An A4 sheet has dimensions of 210 x 297mm whereas a B4 sheet is slightly larger with dimensions of 250 x 353mm. In turn, a C4 sheet is directly in between with a sizing of 229 x 324mm.

B series and C series sizing is most commonly found with envelopes, with an A4 sheet able to fit perfectly into a C4 envelope whereas an A4 sheet folded once will fit into a C5 envelope. The size of paper usually correspond to specific requirements, A4 is the most commonly found size and is used for almost any purpose including signs, posters, letters and general note taking requirements.

Other sizes, such as A0 are used for signage or posters due to its larger size and so forth.

Paper Grammage

The correct terminology for the weight of paper is paper grammage, though it is perhaps more common to see it referred to in terms of ‘weight’ in the United Kingdom. You may notice this when you purchase it as it will usually say something along the lines of ‘80gsm‘ for example.

While gsm is understandable, it is an unofficial unit symbol with the actual symbol being ‘g/m2. That is because the weight of paper is grams per square metre. The weight can determine the purpose with pieces of higher weight, such as anything up to 120gsm, being more likely to be used for official purposes. If it is higher than 160gsm, then it is most often considered card. We’ve listed some common usages by weight below:

  • 80gsm – Letters, schoolwork, notepads, brochures, general print outs
  • 90gsm – Notepads, flyers, letters
  • 100gsm+ – Formal documentation, posters, business cards, calendars

Did You Know?

An interesting fact about paper sizes and weights is that the United States and Canada uses a different system to most countries. In these countries, the most common size is called ‘letter‘ and is slightly wider yet shorter than the standard A4 size with dimensions of 216 x 279mm.

The good news for anyone who finds that they need to buy paper is that we have a range of Paper available to buy on Find My Supplies, so take a look now.

Sarah Jubb