Confused About Paper Weight? Get the 411 Here.
When it comes to specialty paper & paper weight, our customers are generally concerned with paper thickness, how it feels in their hands, and whether or not they will be able to print the paper at home. So naturally, there is concern when a thick card stock and a thinner, lighter sheet are both listed at 80lbs. How can it be?
Paper weight can be a little bit confusing. To answer this common question and clear things up, we're going to explain the standards used to attribute paper weight (also referred to as paper density–the mass of the product per unit of area) in this easy to follow video and article below.
How can a heavier card stock and a lighter paper both weigh 80lbs?
When it comes to paper weight, our customers are generally concerned with paper thickness, how it feels in their hands, and whether or not they will be able to print the paper at home. So naturally, there is concern when a thick card stock and a thinner, lighter sheet are both listed at 80lbs. How can it be? To answer this common question, we're going to explain the standards used to attribute paper weight (also referred to as paper density--the mass of the product per unit of area).
What is the scale used to determine paper weight?
Unfortunately, there isn't just one scale; there are two systems used to measure paper weight. Which system you use depends on your country. If you're the type of person that likes to understand how things work, you'll want to learn about both.
(1) My country uses the metric system.
The simplest and most widely used convention outside of the US is grams per square meter (g/m² or GSM)--the weight in grams of a 1 meter x 1 meter sheet. If a 1 x 1 meter sheet of a particular line of paper weighs 120 grams, then that paper weight is 120 g/m². All grades and paper types use this simple scale. With the metric paper density system, you'll never run into a case where a heavier paper has the same or lower g/m² number as a lighter paper. The higher the number, the heavier the paper. If the number is lower, the paper is lighter.
(2) I'm in North America.
The weights of different paper grades are calculated using each grade's basis weight. First, let's define some key ideas--paper grades, base ream, and basis weight:
Paper Grades: Different types of papers with their own characteristics and end uses
Base Ream: The size and paper count used to weigh a particular paper grade to determine paper density, generally the manufactured size before the paper is cut to the consumer product dimensions
Basis Weight: The weight of a particular paper grade using that grade's base ream size and count
See chart for paper grade descriptions and the base ream counts and dimensions that are used for determining each grade's basis weight:
|Cover||Heavyweight paper used for invitations, program covers, postcards, business cards, and paperback book covers Pre-scoring before folding highly recommended||500 sheets
20 inches x 26 inches
|Text||Lightweight paper commonly used for letterhead, envelopes, program insert sheets, and résumés Easy to fold without scoring||500 sheets
25 inches x 38 inches
|Bond or Writing||Strong, rigid paper used for letterheads and many other printing purposes||500 sheets
17 inches x 22 inches
|Tissue||Light and thin, sometimes decorative sheet||480 sheets
24 inches x 36 inches
|Index||Thin, inexpensive paper with a smooth finish, often used for business reply cards||500 sheets
25 1/2 inches x 30 1/2 inches
|Box cover||Frequently lined with good folding properties and used for making boxes and cartons||500 sheets
20 inches x 24 inches
|Newsprint||Manufactured mostly from mechanical pulps specifically for the printing of newspapers||500 sheets
24 inches x 36 inches
|Paperboard||A heavy weight, thick and rigid, single or multi-layer sheet||1,000 sheets
12 inches x 12 inches
|Bristol||Fine quality cardboard made by pasting several sheets together||500 sheets
22 1/2 inches x 28 1/2 inches
|Blotting||An un-sized paper used to absorb excess ink from freshly written manuscripts, letters and signatures||500 sheets
19 inches x 24 inches
|Hanging, waxing, bag, etc.||The raw stock used in making wallpaper||500 sheets
24 inches x 36 inches
How can a text weight sheet and a card stock both carry the same weight?
Now we can finally answer the original question (which is only a scenario that would surface if the weights were calculated using the US paper density system). Since one paper is a text weight grade and the other is a cover stock grade, they use different size base reams when they are weighed. You should almost think of the two paper grades--text and cover--as being weighed on different scales. Like the product shown at the top of this article, there are often scenarios where a heavier, thicker card stock is rated the same weight as a lighter text weight sheet. We know that an 80lb cover stock is heavier than 80lb text paper because the cover stock uses smaller base ream dimensions than the text paper, yet still holds the same weight.
Paper Stock Weight Calculator
Now that you're familiar with the US density system of different base ream sizes for different paper types vs. the single scale metric system of grams per square inch, you can use our paper weight calculator with confidence. Use it to quickly convert from one system to the other.
If converting from pounds to grams, select "lb", enter the weight, and select the paper type. The equivalent grammage will display in the bottom field.
If converting from grams to pounds, select "grams", enter the weight, then choose the paper type. The weight in pounds will display in the bottom field.