Paper weight - Let's End the Confusion

Publisher:    Time: 04/09/2009

In an effort to help eliminate the "Paper Weight" confusion problem,
we have compiled the comprehensive table listed below.
Now you can compare various types of paper and their "Equivalent Weights."

Definitions:

Basis Weight

The basis weight of a paper is the designated fixed weight of 500 sheets, measured in pounds, in that paper's basic sheet size. It is important to note that the "basic sheet size" is not the same for all types of paper.

Caliper

Caliper refers to the thickness of a sheet of paper expressed in thousandth of an inch. This measurement is taken with a micro meter. Normally, paper caliper should not have more than a + or - 5% variance within a sheet. Generally, the relation between caliper and basis weight .... the greater the caliper (the thicker the paper), the greater the paper weight.

Equivalent Weight

While different paper types have different basic sizes, papers can still be compared by using equivalent weight.

Basis Weight ("Category") Table

Type Paper	Basic Size - 500 Sheets
Bond: Ledger, Mimeo, Duplicator, Rag Paper	17" x 22"
Offset: Book, Text, Coated Paper	25" x 38"
Cover	20" x 26"
Tag Stock	24" x 36"
Index	25-1/2" x 30-1/2"

The Values in the table below are intended to serve as a guide only. They should not be used as specifications because there are variances within the same basis weight due to other characteristics of the papers. Similar weight papers may vary between different paper manufacturers.

Bond Ledger	Offset Text	Cover	Tag	Index	Points	*Caliper(inches)	millimeters	Metric(grams/sq meter)
16	40	22	37	33	3.2	.0032	0.081	60.2 gsm
18	45	24	41	37	3.6	.0036	0.092	67.72 gsm
20	50	28	46	42	3.8	.0038	0.097	75.2 gsm
24	60	33	56	50	4.8	.0048	0.12	90.3 gsm
28	70	39	64	58	5.8	.0058	0.147	105.35 gsm
29	73	40	62	60	6	.0060	0.152	109.11 gsm
31	81	45	73	66	6.1	.0061	0.155	116.63 gsm
35	90	48	80	74	6.2	.0062	0.157	131.68 gsm
36	90	50	82	75	6.8	.0068	0.173	135.45 gsm
39	100	54	90	81	7.2	.0072	0.183	146.73 gsm
40	100	56	93	83	7.3	.0073	0.185	150.5 gsm
43	110	60	100	90	7.4	.0074	0.188	161.78 gsm
44	110	61	102	92	7.6	.0076	0.193	165.55 gsm
47	120	65	108	97	8	.0078	0.198	176.83 gsm
53	135	74	122	110	9	.0085	0.216	199.41 gsm
54	137	75	125	113	9	.009	0.229	203.17 gsm
58	146	80	134	120	9.5	.0092	0.234	218.22 gsm
65	165	90	150	135	10	.0095	0.241	244.56 gsm
67	170	93	156	140	10.5	.010	0.25	252.08 gsm
72	183	100	166	150	11	.011	0.289	270.9 gsm
76	192	105	175	158	13	.013	0.33	285.95 gsm
82	208	114	189	170	14	.014	0.356	308.52 gsm
87	220	120	200	180	15	.015	0.38	312 gsm
105	267	146	244	220	18	.0175	0.445	385.06 gsm

• The darker colored boxes above represent the "most common paper weights" for that category.
• Normal paper manufacturing tolerance within a paper production run is + or - 5% to 7% caliper
• This Table was compiled by Micro Format, Inc.