Unit conversions can be difficult, especially if you don’t know what to convert your units to. But they’re essential to your decision-making process when selecting your packaging material, printing style and more!
Systems of measurement currently in use include the International System of units (SI), the metric system and the imperial system. Depending on geographic location and industry your business is in, unit conversions may be required to effectively communicate with suppliers.
Fortunately, we’ve created the ultimate guide about everything for you to reference in your time of need. Make sure you bookmark this page for future use!
Conversions Between the GSM and PT Unit Systems
GSM stands for grams per square metre and PT stands for point. Both units aid in the measurement of thickness of packaging material, typically paper and cardboard.
A point is equal to 0.001 inches or one thousandth of an inch. 10 points would represent a stock thickness of 0.01 inches.
GSM is the metric equivalent of a point, but it relies on centimetres (cm) and metres (m) instead of inches (in).
Need a quick math recap? An inch corresponds to 2.54 cm or 0.0254 metres because there are a 100 cm in 1 metre.
However, the conversion between the two systems isn’t that easy because the GSM also includes the weight in addition to the area of a material.
Luckily, a lot of the packaging materials are standardized, so you can compare the two based on the following:
- 13 point pulp = 200 gsm
- 14 point uncoated = 270 gsm
- 16 point C2S (solid bleached board coated on 2 sides) = 350 gsm
As a rule of thumb, the higher the GSM, the thicker the stock. Nevertheless, it’s important to understand that more thickness doesn’t simply translate into more weight as it’s solely dependent on the actual material.
Generally, 350-400 gsm include the various paper thicknesses that are mainly used for packaging and business cards. To be honest though, there are a lot of materials that we offer, meaning there are a lot of conversions to process. Look out for our detailed blog post next week on all the facets of GSM and PT.
Pounds (LBs) to GSM
A question we’re often asked is, “How do I convert pounds (lbs) to gsm?” To answer this question, we’ve provided the 2 basic formulas:
1 lb of text paper = 1.48 gsm
For example, if you have 5lbs of text paper, the equivalent in GSM is 1.48 x 5, which equates to 7.4gsm.
1 lb of cover paper = 2.708 gsm
Same situation: if you have 10lbs of cover paper, that equates to 10 x 2.708 or 27.08gsm.
Cover paper is similar to that of card stock which is thicker and more durable than normal printing paper but is thinner and more flexible than regular paperboard.
For most commercially-printed brochures, letterheads, and stationery, the weight of text paper used in the manufacturing process varies from 50-100 lbs.
Ounces to Millilitres
The difference between a fluid ounce (oz) and millimetre (mL) is that an ounce is a U.S. customary unit whereas a mL is a metric unit of volume. Need a recap of volume? Be sure to check out our blog on measurement!
1 Fluid oz is equivalent to 29.574 mL
1 mL = 0.033814 oz
Mils to Millimetres
When we discuss mils and millimetres, we’re looking at the conversion of lengths.
A mils is an imperial or U.S. customary unit of length and is a thousandth of an inch. On the other hand, a millimetre (mm) is a metric unit of length which is equivalent to a thousandth of a metre.
Length in millimetres = 0.0254 x Length in mils
Millimetres to Micrometre
A micrometre, commonly known as a micron (μm) is a SI unit of length which is equivalent to one millionth of a metre. The SI is the most modern form of the metric system. To calculate the conversion from a mm to a micron, the following formulas can be used.
1 mm = 1000 μm
1 μm = 0.001 mm
I’m a Little Confused…
Trust us, we were too when we were first getting into the business. Luckily, you don’t have to worry about it too much.
We understand it can be confusing to have to do all the math when dealing with unit conversions, especially if you’re more accustomed to one system of measurement than another. Feel free to depend on us to do the conversions for you and provide you with all industry specific standards of materials relating to mass and density!
With the help of our experienced in-house production coordinator and excellent customer service, we can meet all your custom packaging needs and provide you with a variety of unit conversions!
Contact us today for a free consultation!