Card Thickness

While nothing can  quite beat the almost surreal experience of wandering around a stationery office or art shop armed with a pair of measuring calipers, here is some information presented in the form of comparison charts that may help you purchase the correct thickness card for your modellling projects without getting strange looks from other customers and shop staff. These comparison tables may also be of help if you are living in a part of the world that uses other ways to specify card thicknesses.

Depending on the thickness of the card required there are various ways that card which is most suitable for modelling is specified:

Cover Stock for thinner card.

Generally used for postcards, business cards and most card crafting hobbies.

Measured by thickness – either millimetres or inches, or by weight – GSM (grams/square metre) or pounds (the weight of one ream of paper of a sheet size based on the category of paper. In the case of cover stock, each sheet being 24″ by 36″).

Millimetres Inches Microns Points GSM Pounds
0.25mm 0.010″ or 10thou 250microns 10pt 240gsm 90lb
0.5mm 0.020″ or 20thou 500microns 20pt 390gsm 140lb
 0.75mm 0.030″ or 30thou 750microns 30pt 570gsm 210lb

Chipboard for thicker card, other names for this include; book boardgrey boardbinding board and Davey board.

Generally used for the covers of hardback books and numerous hobby projects that require thicker card.

Thicknesses are measured in millimetresinches, in Points (one Point being 0.001″ – not to be confused with typographical point measurements), or more rarely by ounce weight.

Millimetres Inches Microns Points Ounces
1mm 0.040″ or 40thou 1000microns 40pt 13oz
1.5mm 0.060″ or 60thou 1500microns 60pt 16oz
2mm 0.080″ or 80thou 2000microns 80pt 24oz

Note: Due to differing densities of card from different card manufacturers which will give varying thickness for the same weight. When used for modelling, it is best whenever possible to purchase card by thickness rather than weight.

Mat Board (US) or Mountboard (UK) for thicker card.

The card used for mounting by picture framers.

Available in various thicknesses. Usually measured in microns in the UK (1400micron thickness is very common). Visit the websites of manufacturers to find the thickness of their various types of mountboard.

In the USA mat board is still often measured in ply (although there is a move to the Point system). Mat board is supplied in either 4 ply, 6 ply or 8 ply. Unfortunately there is no set size for ply so that there can be both 0.040″ (40pt) 4 ply and 0.060″ (60pt) 4 ply, or any thickness in between. In such cases a visit to the manufacturers website, or the calipers and a visit to the picture framing suppliers is your best bet.