Paper Weight Conversion Calculator

Convert paper basis weight in pounds to gsm and back for bond, text, cover, index, bristol and tag, and see the same paper's weight in every grade.

Work & BusinessWorldwideSource: Sylvamo basis weight formula and basic sizesFree, no sign-up

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Basis weight (lb)

Paper grade

A “pound” weight only means something with its grade: 80 lb text and 80 lb cover are very different papers. The result updates as you type.

Grams per square metre

118.4 gsm

80 lb text / book / offset = 118.4 g/m² (basic size 25 × 38 in = 950 in²)

Same paper expressed as	Basis weight
Bond / writing	31.5 lb
Text / book / offset	80 lb
Cover	43.8 lb
Index	65.5 lb
Vellum bristol	54 lb
Tag	72.8 lb

What this page cannot tell you

Thickness (caliper) or stiffness — two papers of the same gsm can feel very different. Mills round their published weights, and catalogues often list rounded equivalents.

How to convert paper weight

Choose the direction. Pounds to gsm, or gsm to pounds.
Enter the weight. For example 80 (lb) or 216 (gsm).
Pick the grade. Bond, text, cover, index, bristol or tag — the pound figure only means something with its grade.
Read the result. gsm, plus the same paper's equivalent in every grade.

10 situations where a paper weight converter helps

Ordering from an overseas printer

Quotes in gsm; your spec is in pounds.

80 lb text vs 80 lb cover

See why they're very different papers.

Business cards

Compare a cover weight in lb with a card stock in gsm.

Printer paper limits

Printers list maximum media weight in gsm; convert your stock.

Wedding invitations

Match a heavy cardstock across suppliers' units.

Flyers and brochures

Choose a text weight by gsm.

Index cards and tags

Index and tag grades have their own basic sizes.

Comparing office paper

20 lb bond is about 75 gsm.

Spec sheets for clients

Give both units on a print spec.

Learning paper grades

The table shows how one sheet is described in every grade.

Where the conversion comes from

US paper is weighed by basis weight: the weight in pounds of a 500-sheet ream of the grade's basic size. Each grade has a different basic size, so the same sheet has different pound weights in different grades. Sylvamo's basis weight calculator gives the conversion: multiply the basis weight by 1406.5 and divide by the area of the basic size in square inches. Basic sizes: bond 17 × 22 in, book/text 25 × 38, cover 20 × 26, index 25.5 × 30.5, vellum bristol 22.5 × 28.5, tag 24 × 36.

The page reproduces Sylvamo's own example: 28 lb bond = 105.3 gsm. 1406.5 itself is just units — grams per pound times square inches per square metre, divided by 500 sheets.

Limits: gsm is weight per area, not thickness or stiffness; two papers of the same gsm can differ in caliper and feel. Mills often publish rounded equivalents. Everything runs in your browser.

Sources

Sylvamo — Basis weight calculator — gsm = basis weight × 1406.5 ÷ basic size area; basic sizes by grade

Frequently asked questions

How do I convert lb to gsm?

Multiply the basis weight by 1406.5 and divide by the basic size area in square inches. For bond (374 in²), 20 lb = 75.2 gsm.

What is 80 lb cover in gsm?

About 216 gsm (80 × 1406.5 ÷ 520).

What is 80 lb text in gsm?

About 118 gsm (80 × 1406.5 ÷ 950).

Why is 80 lb text lighter than 80 lb cover?

Text is weighed on a 25 × 38 in sheet and cover on a smaller 20 × 26 in sheet, so the same 80 lb means a heavier cover paper.

What gsm is normal copy paper?

20 lb bond is about 75 gsm; 24 lb bond about 90 gsm.

Is gsm the same as thickness?

No — it's weight per square metre. Thickness (caliper) is measured separately.