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Commonly specified
American paper weight is based on two
measures:
1. BASIS WEIGHT:
The nominal weight (in pounds) of one ream
(500 sheets) of a particular paper in its
normal manufacturing size (basis size).
2. BASIS SIZE: The normal size of
each type of paper as determined by
manufacturing tradition based on common
usage.
24# Bond
(17" x 22" sheet) |
50# Offset
(25" x 38" sheet) |
Confusion arises because
different basis sizes are used to determine
the basis weight of different grades of
paper. That makes direct comparison of
weights between different grades difficult.
While we generally use paper in 8.5" x 11"
finished sizes, it is the basis size that
determines the basis weight. These are the
most commonly used ‘basis sizes’:
| Bond,
Writing, Stationery, Ledger |
17" x 22" |
| Cover |
20" x 26" |
| Book, Text,
Offset, Coated |
25" x 38" |
| Index |
25.5" x
30.5" |
| Vellum
Bristol Cover |
22.5" x
28.5" |
| Tag |
24" x 36"
|
The chart below shows
the equivalent weights between the most
common grades.
The most commonly used equivalents are
between bond and offset, two papers with
very similar applications. A flyer might be
quoted as 20# Bond by one printer and 50#
Offset by another. The chart will show that
they are essentially the same weight and
could be used interchangeably. However, a
24# Bond would be one step heavier than 50#
Offset as illustrated by the mouse at the
top of the page.
You can also use the chart to determine, for
example, that 60# Cover would be equal
to 47# Bond, or about twice the weight of a
24# Bond letterhead.
European and Asian papers which adhere to
ISO (Metric) Standards are much easier to
compare among themselves. They are all
measured as grams per square meter (gm/m2).
Thus any two papers can be compared directly
to each other without reference to sheet or
basis size.
|
|
Bond |
Offset, Book & Text
|
Cover |
Vellum Bristol Cover |
Index |
Tag |
ISO-
(Metric) |
|
Basis Size* |
17" x 22" |
25" x 38" |
20" x 26" |
22.5" x 28.5 |
"25.5" x 30.5" |
24" x 36" |
grams/
meter2 |
|
Bond, Duplicator, |
13 |
33 |
18 |
22 |
27 |
30 |
49 |
|
Ledger, Mimeo |
15 |
38 |
21 |
25 |
31 |
35 |
56 |
|
& Writing |
16 |
41 |
22 |
27 |
33 |
37 |
60 |
|
|
20 |
51 |
28 |
34 |
42 |
46 |
75 |
|
|
24 |
61 |
33 |
41 |
50 |
55 |
90 |
|
|
28 |
71 |
39 |
48 |
58 |
65 |
105 |
|
|
32 |
81 |
45 |
55 |
67 |
74 |
120 |
|
|
36 |
91 |
50 |
62 |
75 |
83 |
135 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Book, Offset & |
16 |
40 |
22 |
27 |
33 |
36 |
59 |
|
Text |
18 |
45 |
25 |
30 |
37 |
41 |
67 |
|
|
20 |
50 |
27 |
34 |
41 |
45 |
74 |
|
|
24 |
60 |
33 |
40 |
49 |
55 |
89 |
|
|
28 |
70 |
38 |
47 |
57 |
64 |
104 |
|
|
30 |
75 |
41 |
50 |
61 |
68 |
111 |
|
|
31 |
80 |
44 |
54 |
65 |
73 |
118 |
|
|
35 |
90 |
49 |
60 |
74 |
82 |
133 |
|
|
39 |
100 |
55 |
67 |
82 |
91 |
148 |
|
|
47 |
120 |
66 |
80 |
98 |
109 |
178 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Cover |
36 |
91 |
50 |
62 |
75 |
83 |
135 |
|
(Uncoated, Antique |
43 |
110 |
60 |
74 |
90 |
100 |
162 |
|
Finish) |
47 |
119 |
65 |
80 |
97 |
108 |
176 |
|
|
58 |
146 |
80 |
99 |
120 |
133 |
216 |
|
|
65 |
164 |
90 |
111 |
135 |
150 |
243 |
|
|
72 |
183 |
100 |
124 |
150 |
166 |
270 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Vellum Bristol |
33 |
85 |
46 |
57 |
69 |
77 |
125 |
|
Cover |
39 |
100 |
54 |
67 |
81 |
91 |
147 |
|
|
47 |
120 |
65 |
80 |
98 |
109 |
175 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Index |
43 |
110 |
60 |
74 |
90 |
100 |
163 |
|
|
53 |
135 |
74 |
91 |
110 |
122 |
199 |
|
|
67 |
170 |
93 |
115 |
140 |
156 |
253 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Tag |
43 |
110 |
60 |
74 |
90 |
110 |
163 |
|
|
54 |
137 |
75 |
93 |
113 |
125 |
203 |
|
|
65 |
165 |
90 |
111 |
135 |
150 |
244 |
|
|
76 |
192 |
105 |
130 |
158 |
175 |
285 |
|
|
87 |
220 |
120 |
148 |
180 |
200 |
326 |
|
|
|
|
|
|
|
|
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* BASIS SIZE is the common manufactured
sheet size in a particular grade of paper.
The paper’s weight (bold figures) is based
on the weight in pounds of one ream (500
sheets) of that paper in it’s basis size.
For example, “20# Bond” is based on the fact
that 500 sheets of that grade (one ream) in
17" x 22" size (basis size) would weight 20
pounds. By quick calculation, you can
conclude that 500 sheets of 20# Bond in 8.5"
x 11" size (1/4 of 17" x 22" sheet) would
weight 5 pounds.
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