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Back to Industry Standards
Formulas, Weights and Measures
This chapter sets forth
formulas and tables that may be used to determine the relationship of various weights,
sizes and thicknesses of paper. The text is divided into the following sections.
- Basis Weights
- Weight of Sheets of Various Dimensions
- Bulk of Sheets of Various Weights and
Calipers
- Economical Use of Paper Sizes
- Weight and Square Footage of Rolls
Basis Weights
The weight of a given
square area of paper is called its basis weight. This measure could have been established
as the weight of 1000 square feet, or some other convenient dimension. In countries using
the metric system of measurement, it is shown in grams per square meter.
However,
historically, the U.S. paper industry linked the weight to a ream (500 sheets) based on
the most suitable size of the type paper involved. For example, the dimension of 17"
x 22" (four sheets of 8 1/2 x 11") was established for writing papers. The
dimensions used to state the basis weight for various types of paper are as follows:
|
Dimensions |
Square
Inches
in one sheet |
| Writing Paper |
17" x 22" |
374 |
| Printing Paper |
25" x 38" |
950 |
| Cover |
20" x 26" |
520 |
| Printing Bristol |
22 1/2" x 28 1/2" |
641 |
| Index Bristol |
25 1/2" x 30 1/2" |
778 |
| Newsprint, Tag & Tissue |
24" x 36" |
864 |
The following table
shows the equivalent weights of various types of paper based on the respective dimensions
used.
| |
BOND
17" x 22" |
PRINTING
25" x 38" |
COVER
20" x 26" |
BRISTOL
22 1/2" x 28 1/2" |
INDEX
25 1/2" x 30 1/2" |
NEWSPRINT,
TAG
& TISSUE
24" x 36" |
BOND
LEDGER
MIMEO
DUPLICATOR
WRITINGS
|
13
16
20 |
33
41
51 |
18
22
28 |
22
27
34 |
27
38
42 |
30
37
46 |
24
28
32 |
61
71
81 |
33
39
45 |
41
48
55 |
50
58
67 |
56
64
74 |
36
40
44 |
91
102
112 |
50
56
61 |
62
69
75 |
75
83
92 |
83
93
102 |
BOOK
OFFSET
TEXT
|
12
16
18 |
30
40
45 |
16
21
24 |
20
27
30 |
25
32
37 |
27
36
41 |
20
24
28 |
50
60
70 |
27
32
38 |
34
40
47 |
41
49
57 |
45
55
64 |
31
35
39 |
80
90
100 |
43
48
54 |
54
60
67 |
66
74
81 |
73
82
91 |
47
59 |
120
150 |
65
80 |
80
100 |
98
123 |
109
136 |
COVER
|
29
36
43 |
73
91
110 |
40
50
60 |
49
62
74 |
60
75
90 |
66
82
100 |
47
58
65
72 |
119
146
164
183 |
65
80
90
100 |
80
99
111
124 |
97
120
135
150 |
108
134
149
166 |
MILL
BRISTOL
|
58
70
82 |
148
176
207 |
81
97
114 |
100
120
140 |
121
146
170 |
135
162
189 |
93
105
117 |
237
267
296 |
130
146
162 |
160
180
200 |
194
218
243 |
216
242
269 |
PRINTING
BRISTOL |
52
59
71
83
95 |
133
151
181
211
241 |
73
83
99
116
132 |
90
102
122
143
163 |
109
123
148
173
198 |
121
137
165
192
219 |
INDEX
BRISTOL |
43
53
67 |
110
135
170 |
60
74
93 |
74
91
115 |
90
110
140 |
100
122
156 |
82
105 |
208
267 |
114
146 |
140
182 |
170
220 |
189
244 |
TAG
|
43
54
65 |
110
137
165 |
60
75
90 |
74
93
111 |
90
113
135 |
100
125
150 |
76
87
109
130 |
192
220
275
330 |
105
120
151
181 |
130
148
186
222 |
158
180
225
270 |
175
200
250
300 |
Weights of Sheets of Various
Dimensions
The weight of any
size sheet is equal to the ratio of its square area to the square area of the base size
for that type paper.
For example:
Assume that the sheet
of interest is 70 lb. printing paper in the size 42" x 58".
As noted previously,
the size on which the 70 lb. basis weight is based is 25" x 38". The square area
of the basic size is equal to 25" x 38" = 950 square inches.
Determine the square
area of the sheet of interest
42" x 58" = 2436 square inches.
Divide the square
area of the sheet of interest by the square area of the base
2564 by 950 =2.564
Since the 42" x
58" sheet is 2.564 times bigger than the 25" x 38", it must weigh that much
more. Therefore, multiply 70 lbs. by 2.564 to determine the weight of 500 sheets 42"
x 58".
70 x 2.564 = 179 lbs.
If the weight for
1000 sheets is desired, multiply the 500 sheet weight by 2.
Tables showing the
weight per thousand sheets of the various types of printing and writing papers are
provided on the following three pages.
PRINTING
PAPERSWeights Per M Sheets
Basis 25" x 38"
BASIS |
30 |
35 |
40 |
45 |
50 |
60 |
70 |
80 |
90 |
100 |
120 |
150 |
17-1/2
x 22-1/2 |
25 |
29 |
33 |
37 |
41 |
50 |
58 |
66 |
75 |
83 |
99 |
124 |
19 x 25
|
30 |
35 |
40 |
45 |
50 |
60 |
70 |
80 |
90 |
100 |
120 |
150 |
23 x 29
|
42 |
49 |
56 |
63 |
70 |
84 |
98 |
112 |
126 |
140 |
169 |
|
23 x 35
|
51 |
59 |
68 |
76 |
85 |
102 |
119 |
136 |
152 |
170 |
204 |
|
22-1/2
x 35 |
50 |
58 |
66 |
75 |
83 |
99 |
116 |
133 |
149 |
166 |
199 |
249 |
24 x 36
|
54 |
64 |
72 |
82 |
90 |
110 |
128 |
146 |
164 |
182 |
218 |
272 |
25 x 38
|
60 |
70 |
80 |
90 |
100 |
120 |
140 |
160 |
180 |
200 |
240 |
300 |
26 x 40
|
66 |
76 |
88 |
98 |
110 |
132 |
154 |
176 |
198 |
218 |
262 |
328 |
28 x 42
|
74 |
86 |
100 |
112 |
124 |
148 |
174 |
198 |
222 |
248 |
298 |
372 |
28 x 44
|
78 |
90 |
104 |
116 |
130 |
156 |
182 |
208 |
234 |
260 |
312 |
390 |
30-1/2
x 41 |
78 |
92 |
106 |
118 |
132 |
158 |
184 |
210 |
236 |
264 |
316 |
396 |
32 x 44
|
88 |
104 |
118 |
134 |
148 |
178 |
208 |
238 |
266 |
296 |
356 |
444 |
33 x 44
|
92 |
106 |
122 |
138 |
152 |
184 |
214 |
244 |
276 |
306 |
366 |
460 |
35 x 45
|
100 |
116 |
132 |
150 |
166 |
198 |
232 |
266 |
298 |
332 |
398 |
498 |
36 x 48
|
108 |
128 |
144 |
164 |
180 |
220 |
254 |
292 |
328 |
364 |
436 |
544 |
38 x 50
|
120 |
140 |
160 |
180 |
200 |
240 |
280 |
320 |
360 |
400 |
480 |
600 |
41 x 54
|
140 |
164 |
186 |
210 |
234 |
280 |
326 |
372 |
420 |
466 |
560 |
700 |
44 x 64
|
178 |
208 |
238 |
266 |
296 |
356 |
414 |
474 |
534 |
592 |
712 |
888 |
35 x 46
|
102 |
118 |
136 |
152 |
170 |
204 |
238 |
272 |
306 |
338 |
406 |
|
38 x 52
|
124 |
146 |
166 |
188 |
208 |
250 |
292 |
332 |
374 |
416 |
500 |
|
41 x 61
|
156 |
184 |
212 |
236 |
264 |
316 |
368 |
420 |
472 |
528 |
632 |
|
42 x 58
|
154 |
180 |
206 |
230 |
256 |
308 |
358 |
410 |
462 |
512 |
615 |
|
44 x 66
|
178 |
208 |
238 |
266 |
296 |
356 |
414 |
474 |
534 |
592 |
712 |
|
46 x 69
|
201 |
234 |
267 |
301 |
334 |
400 |
468 |
534 |
602 |
668 |
802 |
|
52 x 76
|
250 |
292 |
332 |
374 |
416 |
500 |
582 |
666 |
748 |
832 |
998 |
|
BONDS and WRITING
PAPERSWeights Per M Sheets
Basis 17" x 22"
BASIS |
13 |
16 |
20 |
24 |
28 |
32 |
36 |
40 |
44 |
8-1/2 x
11 |
6.50 |
8.00 |
10.00 |
12.00 |
14.00 |
16.00 |
18.00 |
20.00 |
22.00 |
8-1/2 x
13 |
7.68 |
9.44 |
11.81 |
14.18 |
16.54 |
18.90 |
21.27 |
23.63 |
26.00 |
8-1/2 x
14 |
8.26 |
10.18 |
12.72 |
15.26 |
17.81 |
20.36 |
22.90 |
25.45 |
28.00 |
11 x 17
|
13.00 |
16.00 |
20.00 |
24.00 |
28.00 |
32.00 |
36.00 |
40.00 |
44.00 |
16 x 21
|
23-1/2 |
29 |
36 |
43 |
50-1/2 |
57-1/2 |
65 |
72 |
79 |
16 x 42
|
47 |
58 |
72 |
86 |
101 |
115 |
130 |
144 |
158 |
17 x 22
|
26 |
32 |
40 |
48 |
56 |
64 |
72 |
80 |
88 |
17-1/2
x 22-1/2 |
27 |
34 |
42 |
51 |
59 |
67 |
76 |
84 |
93 |
17 x 26
|
31 |
38 |
47 |
57 |
66 |
76 |
85 |
95 |
104 |
17 x 28
|
33 |
41 |
51 |
61 |
71-1/2 |
81-1/2 |
92 |
102 |
112 |
18 x 23
|
29 |
35-1/2 |
44-1/2 |
53 |
62 |
71 |
80 |
89 |
97-1/2 |
18 x 46
|
58 |
71 |
89 |
106 |
124 |
142 |
160 |
178 |
195 |
19 x 24
|
32 |
39 |
49 |
58-1/2 |
68-1/2 |
78 |
88 |
98 |
107 |
20 x 28
|
39 |
48 |
60 |
72 |
84 |
96 |
108 |
120 |
132 |
21 x 32
|
47 |
58 |
72 |
86 |
101 |
115 |
130 |
144 |
158 |
22 x
25-1/2 |
39 |
48 |
60 |
62 |
84 |
96 |
108 |
120 |
132 |
22 x 34
|
52 |
64 |
80 |
96 |
112 |
128 |
144 |
160 |
176 |
22-1/2
x 22-1/2 |
35 |
43 |
54 |
65 |
76 |
87 |
97 |
108 |
119 |
22-1/2
x 34-1/2 |
54 |
66 |
83 |
99 |
116 |
133 |
149 |
166 |
183 |
22-1/2
x 35 |
56 |
67 |
84 |
101 |
118 |
134 |
152 |
168 |
186 |
23 x 36
|
58 |
71 |
89 |
106 |
124 |
142 |
160 |
178 |
195 |
24 x 38
|
64 |
78 |
98 |
117 |
137 |
156 |
176 |
196 |
214 |
24-1/2
x 24-1/2 |
42 |
51-1/2 |
64 |
77 |
90 |
103 |
116 |
128-1/2 |
141 |
24-1/2
x 28-1/2 |
49 |
60 |
75 |
90 |
105 |
119-1/2 |
134-1/2 |
149-1/2 |
164-1/2 |
24-1/2
x 29 |
49-1/2 |
61 |
76 |
91 |
106-1/2 |
122 |
137 |
152 |
167 |
24-1/2
x 38-1/2 |
66 |
81 |
101 |
121 |
141-1/2 |
161-1/2 |
182 |
202 |
222 |
24-1/2
x 39 |
66 |
82 |
102 |
122 |
144 |
164 |
184 |
204 |
225 |
25-1/2
x 44 |
78 |
96 |
120 |
144 |
168 |
192 |
216 |
240 |
264 |
26 x 34
|
62 |
76 |
94 |
114 |
132 |
152 |
170 |
189 |
208 |
28 x 34
|
66 |
82 |
102 |
122 |
143 |
163 |
184 |
204 |
224 |
34 x 44
|
104 |
128 |
160 |
192 |
224 |
256 |
288 |
320 |
352 |
35 x 45
|
109 |
135 |
168 |
202 |
236 |
270 |
303 |
337 |
371 |
COVER
PAPERWeights Per M Sheets
Basis 20" x 26"
BASIS
|
50
|
60
|
65
|
80
|
90
|
100
|
130
|
20 x 26
|
100 |
120 |
130 |
160 |
180 |
200 |
260 |
22-1/2
x 28-1/2 |
123 |
148 |
160 |
197 |
222 |
246 |
320 |
23 x 29
|
128 |
154 |
167 |
205 |
231 |
256 |
334 |
23 x 35
|
155 |
186 |
201 |
248 |
279 |
310 |
402 |
26 x 40
|
200 |
240 |
260 |
320 |
360 |
400 |
520 |
35 x 46
|
310 |
372 |
402 |
496 |
558 |
620 |
804 |
INDEX
BRISTOLWeights Per M Sheets
Basis 25-1/2" x 30-1/2"
BASIS
|
90
|
110
|
140
|
170
|
220
|
20-1/2
x 24-3/4 |
117 |
144 |
182 |
222 |
286 |
22-1/2
x 28-1/2 |
148 |
182 |
230 |
280 |
362 |
22-1/2
x 35 |
182 |
223 |
284 |
344 |
444 |
25-1/2
x 30-1/2 |
180 |
220 |
280 |
340 |
440 |
28-1/2
x 45 |
296 |
364 |
460 |
560 |
724 |
PRINTING
BRISTOLWeights Per M Sheets
Basis 23" x 35"
BASIS
|
47
|
80
|
100
|
120
|
22-1/2
x 28-1/2 |
134 |
160 |
200 |
240 |
23 x 35
|
168 |
201 |
252 |
302 |
26 x 40
|
216 |
260 |
|
|
TAGWeights Per M
Sheets
Basis 24" x 36"
BASIS
|
90
|
100
|
125
|
150
|
175
|
200
|
250
|
22-1/2
x 28-1/2 |
134 |
148 |
186 |
223 |
260 |
297 |
371 |
24 x 36
|
180 |
200 |
250 |
300 |
350 |
400 |
500 |
28-1/2
x 45 |
268 |
296 |
372 |
446 |
520 |
594 |
742 |
Bulk of Sheets of Various
Weights and Calipers
The thickness of the
sheet can be an important factor in the production, delivery and use of paper. This
property influences the strength of the sheet and the height formed when a series of
sheets are placed top of each other.
This section presents
procedures and tables that may be used to determine the bulk of papers of interest to the
reader.
Bulk Determination
Micrometer
Reading |
Pages Per
Inch |
Micrometer
Reading |
Pages Per
Inch |
Micrometer
Reading |
Pages Per
Inch |
.007
|
1142 |
.019 |
420 |
.031 |
258 |
.0075
|
1066 |
.0195 |
410 |
.0315 |
254 |
.008
|
1000 |
.020 |
400 |
.032 |
250 |
.0085
|
942 |
.0205 |
390 |
.0325 |
246 |
.009
|
888 |
.021 |
380 |
.033 |
242 |
.0095
|
842 |
.0215 |
372 |
.0335 |
238 |
.010
|
800 |
.022 |
364 |
.034 | |