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Paper Weight Converter

Convert paper weights between gsm and US pound grades (bond, text, cover, index, bristol and tag). You also get every equivalent weight, an approximate thickness in mm and points, and what that weight is typically used for.

Paper weight

The number printed on the ream, e.g. 20 (lb) or 80 (gsm).

From

Paper finish (for thickness)

Thickness = gsm × bulk. Real caliper varies by mill; check the spec sheet for exact values.

Enter your values to see the result.

How to use the Paper Weight Converter

Enter the paper weight printed on the package, for example 20 or 80.
Choose the grade it is in: gsm, or the pound grade (bond, text, cover, index…).
Choose the unit you want to convert to.
Pick the paper finish to estimate thickness (coated papers are thinner for the same weight).
Read the result and the full list of equivalents, or copy them with one click.

How paper weight conversion works

In the US, paper is sold by basis weight: the weight in pounds of 500 sheets cut to a basis size that depends on the grade. Grams per square meter (gsm, g/m²) measures the same thing for a single square meter, so it does not depend on the grade. To convert, divide the ream weight by the ream area:

gsm = lb × 453.592 ÷ (500 × width × height × 0.00064516)

with the width and height of the basis sheet in inches. That gives a fixed factor for each grade:

Grade	Basis size	1 lb =	1 gsm =
Bond / Writing / Ledger	17 × 22 in	3.760 gsm	0.266 lb
Text / Book / Offset	25 × 38 in	1.480 gsm	0.676 lb
Cover / Card	20 × 26 in	2.704 gsm	0.370 lb
Index	25.5 × 30.5 in	1.808 gsm	0.553 lb
Bristol	22.5 × 28.5 in	2.195 gsm	0.456 lb
Tag / Newsprint	24 × 36 in	1.627 gsm	0.614 lb

Common paper weights at a glance

Common name	gsm	Typical use
20 lb bond / 50 lb text	75	Everyday copy and printer paper (US)
24 lb bond / 60 lb text	90	Reports, letterhead, double-sided printing
28 lb bond / 70 lb text	105	Résumés, presentations, premium flyers
80 lb text	118	Brochures, booklet pages, posters
100 lb text	148	Magazine covers, heavy flyers
65 lb cover	176	Light card, menus, thin covers
80 lb cover	216	Postcards, report covers
110 lb index	199	Index cards, tabs, file cards
100 lb cover	270	Greeting cards, invitations
130 lb cover	352	Business cards, premium postcards

Estimating paper thickness

Thickness (caliper) is weight multiplied by bulk, the volume per gram: thickness (µm) = gsm × bulk (cm³/g). Uncoated office paper has a bulk around 1.2–1.3, coated gloss paper around 0.8–0.95, and bulky or recycled stock 1.4 or more. In the US, thickness is often given in points, where 1 pt = 0.001 inch = 25.4 µm. These are estimates; the paper's technical data sheet gives the exact caliper.

Frequently asked questions

How do I convert lb paper weight to gsm?

Multiply by the factor for the paper grade: bond × 3.76, text × 1.48, cover × 2.70, index × 1.81, bristol × 2.20 and tag × 1.63. For example, 20 lb bond × 3.76 = 75.2 gsm.

Why does 80 lb text weigh less than 80 lb cover?

The pound weight is the weight of 500 sheets at the grade's basis size, and each grade uses a different size. Text paper uses large 25 × 38 inch sheets, cover uses 20 × 26 inch sheets, so 80 lb text is about 118 gsm while 80 lb cover is about 216 gsm.

What gsm is normal printer paper?

Standard office copy paper is 20 lb bond in the US (about 75 gsm) and 80 gsm in most other countries. 24 lb bond (about 90 gsm) is a common upgrade for reports and résumés.

What gsm is card stock?

Light card stock starts around 170–200 gsm (65–80 lb cover). Postcards and greeting cards are usually 250–300 gsm (90–110 lb cover), and business cards are typically 300–400 gsm.

Is gsm the same as thickness?

No. gsm measures weight per square meter. Thickness (caliper) also depends on how dense the paper is: coated gloss paper is thinner than uncoated paper of the same gsm. The thickness shown here is an estimate; use the mill's spec sheet for exact caliper.

What is basis weight?

Basis weight is the weight in pounds of one ream (500 sheets) of paper cut to the grade's standard basis size. It is the US and Canadian system; most of the world uses gsm (grams per square meter) instead.

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