Paper weight explained: text vs cover, lb vs pt vs gsm

Why 100 lb paper can be thinner than 80 lb paper

Paper weight in the US is a basis weight: what 500 sheets of that paper weigh at its basis size, in pounds. The catch is that each grade of paper has a different basis size. Text paper is weighed at 25 x 38 inches. Cover stock is weighed at 20 x 26 inches. Because the cover sheet is smaller, 500 of them weigh less for the same thickness of paper, so the number comes out lower.

So 100 lb text is a heavy flyer or brochure sheet you can still fold easily. 80 lb cover is a light card stock. Put them side by side and the 80 lb cover is the stiffer, heavier sheet, even though its number is smaller. Comparing pounds only works inside the same grade.

The grades you will hear at the counter

Each of these has its own basis size. That is why the numbers do not line up across grades:

• Bond (17 x 22 in): copy paper, letterhead, forms. 20 lb and 24 lb bond are everyday office weights.
• Text (25 x 38 in): flyers, brochures, booklet insides, newsletters. Usually 70 lb to 100 lb.
• Cover (20 x 26 in): business cards, postcards, folders, booklet covers. Usually 65 lb to 130 lb.
• Index (25.5 x 30.5 in): smooth, stiff, uncoated card used for index cards, tabs and some forms.

GSM is the number that compares across grades

Grams per square meter (gsm, sometimes g/m2) is the weight of one square meter of the paper. There is no basis size to trip over, so 216 gsm is heavier than 148 gsm no matter what the paper is called. Most of the world specifies paper this way, and many US mill spec sheets list gsm next to pounds.

If a quote or a sample book gives you gsm, use it. It is the cleanest way to compare a text sheet against a cover sheet. A quick rule: multiply text pounds by about 1.48 to get gsm, and cover pounds by about 2.7.

Approximate conversion table

These are the commonly published equivalents. They are approximate: real sheets vary slightly by mill and finish, and conversions get rounded. Use them to compare, then look at the actual paper.

• 20 lb bond = about 50 lb text = about 75 gsm
• 24 lb bond = about 60 lb text = about 90 gsm
• 28 lb bond = about 70 lb text = about 105 gsm
• 32 lb bond = about 80 lb text = about 120 gsm
• 100 lb text = about 148 gsm
• 65 lb cover = about 176 gsm
• 80 lb cover = about 216 gsm
• 110 lb index = about 199 gsm
• 100 lb cover = about 270 gsm
• 130 lb cover = about 352 gsm

Points measure thickness, not weight

A point (pt) is one thousandth of an inch of caliper. A 14 pt card is about 0.014 inch thick and a 16 pt card about 0.016 inch. Card stocks for business cards and postcards are often sold by points because thickness is what you feel in the hand.

Weight and thickness are related but they are not the same thing. Coating is dense, so a gloss cover is thinner than an uncoated cover of the same weight. Two papers that both say 100 lb cover can feel different for that reason alone. If stiffness matters, ask for the caliper in points.

What we would put each job on

Starting points, not rules. Your design and budget may push you up or down a weight.

• Letterhead: 24 lb bond or 70 lb uncoated text, and tell us if it will go through a laser printer.
• Flyers handed out at an event: 80 lb or 100 lb gloss text.
• Tri-fold brochures: 100 lb gloss or silk text. Heavier than that and the folds start to crack unless the sheet is scored.
• Booklet insides: 70 lb to 100 lb text, with an 80 lb or 100 lb cover if you want a self-cover feel to stop.
• Postcards for the mail: a 14 pt or 16 pt card, or 100 lb cover and up. Check the USPS thickness minimums for your mail class.
• Business cards: 14 pt or 16 pt. Anything thinner reads as cheap the moment someone takes it.
• Presentation folders: 12 pt or 14 pt so the pockets hold their shape.

Ask for a sample before you commit

Numbers on a screen tell you very little about how a sheet feels. If you are choosing paper for something people will hold, like a business card, a wedding program or a folder, ask to see a printed sample or a swatch of the stock. Five seconds with the paper settles what an hour of reading cannot.