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Metric Measurements
The metric system
of measurement is used in almost all countries throughout the world. The notable
exception is the United States.
The U. S. Congress
established the metric system as the “preferred system of weights and measures”
as part of the Omnibus Trade and Competitiveness Act of 1988. An Executive Order
issued by President George Bush in l991 requires every federal agency to use metric
measurements in grants, contracts and other business related activities after October 1,
1992, “unless it is not economically feasible or is likely to cause significant
inefficiencies or loss of market to U. S. firms.”
For the marketing
of paper, the conversion of the customary units to the metric system may be accomplished
by the application of formulas to move from inches to millimeters and pounds to grams.
Sizes
The size of paper in
metric measure is stated in millimeters. There are 25.4 millimeters in one inch.
The procedure is to multiply the inches by 25.4, and round off to the nearest
millimeter.
For example: to
convert the size of standard letter size from inches to millimeters 8 1/2" x
25.4 mm = 215.9 mm and 11" x 25.4 mm = 279.4 mm. The measurement therefore
becomes 216 mm x 279 mm.
Basis weight
The basis weight of
paper and paperboard is stated in grams per square meter (g/m^{2} ).
To convert from basis
weight in pounds the following formula may be applied equally to basis ream weights of any
dimension, e.g. 17" x 22", 25" x 38", 24" x 36".
Multiply the basis
weight by 1406.13 and divide by the square inches in the base sheet.
For example:
To convert from 20
lb. 17" x 22"/500:
20 lbs. x 1406.13 ÿ 374 = 75 g/m^{2}
^{To convert from
50 lb. 25" x 38"/500:
50 lbs. x 1406.13 ÿ} 950 = 74 g/m^{2}
^{To convert from
g/m2} to pounds the procedure is reversed:
Multiply the g/m^{2}
by the square inches in the base sheet and divide by 1406.13.
Tables follow and
show the grams per square meter values for the most common basis weights.
Total Weight
The total weight
should either be expressed in kilograms or metric tons.
To convert:
From 
To 
Multiply by 
pounds 
kilograms

0.4536 
short tons 
metric
tons 
0.9072 
metric tons 
short
tons 
1.1023 
How to write metric units
 When rounding off metric units to
the nearest whole unit use the procedure now used for the customary units.
When the decimal is
less than 0.5, the first whole number to the left of the decimal point does not change.
When the decimal is
0.5 or more, the first whole number to the left of the decimal point is increased by 1.
 If a number is less than one, a
zero should be written to the left of the decimal point, e.g. 0.25.
 If it is desired to separate digits
in groups of three do not use a comma. Use only a space.
 Periods are not
used after symbols, e.g. mm for millimeters.
 Although an “s” added to
the names of units to make them plural, symbols are the same for both
singular and plural.
Metric units of measure and
their symbols
UNIT 
SYMBOL 
meter

m 
centimeter

cm 
kilometer

km 
millimeter

mm 

gram

g 
kilogram

kg 
milligram

mg 

metric
tonnes 
t 
grams
per square meter 
g/m^{2}

^{PREFIXES} 
NUMERIC 
^{mega}

1 000 000 
^{kilo}

1
000 
^{hecto}

100

^{deca}

10

^{deci}

.1

^{centi}

.01

^{milli}

.001

^{Conversion of the U. S.
customary weights and measures to metric measurements}
^{CUSTOMARY} 
METRIC 
^{1 inch} 
25.4 millimeters 
^{1 foot} 
.3048 meters 
^{1 yard} 
.9144 meters 
^{1 ounce} 
28.3495 grams 
^{1 pound} 
453.5924 grams =
.4536 kilograms 
^{8 1/2" x 11"} 
216 mm x 279 mm 
^{Conversion of metric
measurements to U. S. customary weights and measures}
^{METRIC} 
CUSTOMARY 
^{1
meter} 
39.37
inches 
^{1
kilogram} 
2.2046
pounds 
^{1
metric ton} 
1.1023
short tons 
^{A4/
210 mm x 297 mm} 
8
1/4" x 11 11/16" 
^{International
Standards Organization’s paper sizes}
^{In reference to
sheeted paper, many countries in the world use sizes set in the International Standards
Organization’s document ISO 216. The ISO sizes are a series of sizes designated
“A”, “B” and “C”, having a lengthtowidth ratio of 1.414.
}
^{The
“A” series is the one predominantly used. It starts with the AO size which
has an area equal to a square meter. Each time the long side of the paper is cut in
half the new size maintains the same 1.414 ratio. When AO is cut in half, two sheets
of size A1 are created. The half cut of A1 provides the A2 size. This
procedure may be followed down to the A8 size. The most common however is A4 which
is equal to 210mm x 297mm (8 1/4" x 11 11/16").}
ISO216 — A
SIZES
^{Some
organizations and individuals in the United States and Canada have assumed that conversion
to metric units involves a change to these ISO sizes. However, 216mm x 279mm, (8
1/2" x 11") is just as metric as 210mm x 297mm (ISO A4 size).}
Basis weight and grams
per square meter
for most common paper weights
17" x 22"
lbs. 
20" x 26"
lbs. 
24" x 36"
lbs. 
25" x 38"
lbs. 
Grams/Sq.
Meter
(q/m^{2}) 
9 



34 



24 
36 
11 



41 



30 
44 
13 

30 
33 
49 


32 
35 
52 
15 



56 



40 
59 
16 



60 


40 

65 



45 
67 
18 



68 



50 
74 
20 



75 


50 

81 



60 
89 
24 



90 


60 

98 



70 
104 
28 



105 

40 


108 


70 

114 



80 
118 
32 



120 


80 

130 



90 
133 
36 
50 


135 


90 

146 



100 
148 

60 


162 


100 

163 

65 


176 



120 
178 

70 


189 
Basic formula: To
convert from basis weight in pound to grams per square meter, multiply the basis weight by
1406.13 and divide by the square inches in the base sheet. For example, to convert
from 20 lb. 17" x 22"/500, multiply 20 lbs. by the constant 1406.13 and divide
by 374 = 75 g/m^{2}.
