Conversion factors

Here we present two tables of the conversion factors for customary and SI units related to paper products.

Customary units to SI units

QuantityOther unitsMultiply byFor SI unit
Grammage (mass on ream basis) Pounds per ream (lb/ream) per 3000 square feet (lb/3000 ft2) 1.6275 Grams per square meter (g/m2)
Grammage (mass in grams per square meter) Pounds per 1000 square feet (lb/1000 ft²) 4.8824 Grams per square meter (g/m2)
Thickness  Millimetres (mm)
Mils (or points or thousandths of an inch)
1000
25.4 
Micrometers (µm)
Apparent density Kilograms per cubic centimetre (g/cm²)
Pounds per cubic foot (lb/ft²)
1000
16.01846 
Kilograms per square meter (kg/m2) 
Tensile strenght

Kilograms-force per 15 millimetre width (kgf/15 mm)
Pounds-force per inch (lbf/in)

0.65378
0.175127
Kilonewtons per meter (kN/m)
Tensile index (replaced breaking length) Kilometres breaking length (Km)  9.80665  Newtonmeters per gram (N m/g)
Tensile energy absorption (TEA) Kilograms-force meters per square meter (Kgf m/m2)
Foot pinds-force per square foot (ft lbf/ft2)
9.80665
14.5939
Joules per square meter (J/m²) 
Tearing strenght Grams-force (gf)  9.80665  Millinewtons (mN)
Tear index (replaced tear factor)  Computed as 100 grams-force per gram per square meter (100 gf(g/m²)) 0.0980665 Millinewtons sq. meters per gram (mN m²/g)
Bursting strength Kilograms-force per square centimetre (kgf/cm²) 
Pounds-force per square inch - psi (lbf/in²)
98.0665
6.89476
Kilopascals (kPa)
Burst index (replaced burst factor) computed as grams-force per square centimetre per gram per square meter ((gf/cm² /(g/m²)) 0.0980665 Kilopascals sq. meters per gram (kPa m²/g)
Z-direction strength properties (unit as appropriate) Kilograms-force per square centimetre (kgf/cm²)
Pounds-force per square inch (lbf/in²)
Foot pounds-force per square inch (ft lbf/in²)
98.0665
6.89476
2101.5
Kilopascals (kPa)
Kilopascals (kPa)
Joules per square meter (J/m²)
Concora Medium Test (CMT) Kilograms-force (kgf)
Pounds-force (lbf)
9.80665
4.44822
Newtons (N)
Ring Crush Test (RCT) Kilograms-force per centimetre (kgf/cm)
Pounds-force (for a 6-inch length) (lbf/6 in)
0.980665
0.02919
Kilonewtons per meter (kN/m)
Edgewise compressive strength (ECT) Pounds-force per inch (lbf/in) 0.175127 Kilonewtons per meter (kN/m)
Flat crush resistance of corrugated board (FCT) Kilograms-force per square centimetre (kgf/cm²) 98.0665 Kilopascals (kPa)
Flat crush resistance of corrugated board (FCT) Pounds-force per square inch (lbf/in²) 6.89476 Kilopascals (kPa)

Length

Length
1 meter 1.094 yards
1 centimetre 0.394 inches
1 millimetre 0.039 inches
 1 yard  0.914 meters
 1 foot 0.305 meters 
 1 inch 2.54 centimetres 

 Weight

Weight
1 metric tonne
0.984 long tons
1.102 short tons
1 kilogram
2.306 pounds
35.274 ounces
1 gram

0.035 ounces

1 pound

453.6 grams

1 ounce

28.35 grams

Surface 

Surface
1 square meter
1.196 square yards
10.764 square feet
1550 square inches
1 square centimetre 0.155 square inches
1 square millimetre 0.002 square inches
1 acre 0.4046 hectare
1 square yard 0.836 square meters
1 square foot
929 square centimetres
0.0929 square meters
1 square inch 6.452 square centimetres