Composition of Dry Air at Sea Level Component Mole Per Cent Molar Mass N2 78.084 28.013 O2 20.948 31.998 Ar 0.934 29.948 CO2 0.0314 44.010 Ne 0.001818 20.183 He 0.000524 4.003 CH4 0.002 16.043 Kr 0.000114 83.80 H2 0.00005 2.016 N2O 0.00005 44.013 Xe 0.0000087 131.30

To convert from              to                      multiply by 
mile                    kilometer (km)          1.61       
inch (in)               millimeter (mm)         25.4
inch (in)               centimeter (cm)         2.54  
inch (in)               meter (m)               0.025       
foot (ft)               meter (m)               0.305       
yard (yd)               meter (m)               0.914

To convert from              to                      multiply by 
square foot (ft2)     square meter (m2)               0.093    
square inch (in2)     square meter (m2)              0.00065    
square yard (yd2)     square meter (m2)              0.836    
acre (ac)               hectare (ha)                 0.4047

To convert from              to                      multiply by 
cubic inch (in3)      cubic meter (m3)                0.0000164     
cubic foot (ft3)      cubic meter (m3)                 0.028      
cubic yard (yd3)      cubic meter (m3)                0.765       
gallon (gal)            liter                        4.546   
gallon (gal)            cubic meter (m3)              0.0038      
fluid ounce (fl oz)     milliliters (ml)             29.57        
fluid ounce (fl oz)     cubic meter (m3)             0.00003

To convert from              to                      multiply by
pound (lb)              kilogram (kg)                  0.454
pound (lb)              newton (N)                     4.45

To convert from              to                      multiply by
Mass (weight) 
        pound (lb)            kilogram (kg)             0.4536
        ton, 2000 lb          kilogram (kg)             907.185
        grain                 kilogram (kg)             0.000065
        
Mass per volume (density) 
        pound per cubic       kilogram per cubic        16.02
          foot (pcf)           meter (kg/m3)
        pound per cubic       kilogram per cubic        0.593
          yard (lb/cu yd)      meter (kg/m3)

Temperature
To convert from                       to                      use equation
        degree Fahrenheit (F)     degree Celsius (C)            c=(F-32)/1.8
        degree Fahrenheit (F)     kelvin (K)                    k = (F+459.7)/1.8
        kelvin (K)                degree Celsius (C)            c=k-273.15



Temperature Conversion Factors


Energy and heat
To convert from              to                      multiply by

        British thermal           joule (J)           1055.06
         unit(Btu)
        calorie (cal)             joule (J)             4.187
        kilowatt-hour (kwh)       joule (J)              3,600,000
        British thermal unit      watt (W)              0.2931
         per hour (Btu/hr)

To convert from                   to                      multiply by
Power
        horsepower (hp)           watt (W)                  745.69
           (550 ft-lb/sec)
Velocity
         mile per hour (mph)      kilometer per hour(km/hr) 1.61
         mile per hour (mph)      meter per second (m/s)    0.45

Quantity            From English           To Metric             Multiply
                      Units                  Units                 by

Length                mile                    km                 1.609
                      yard                    m                  0.914
                      foot                    m                  0.305
                      inch                    mm                 25.4

Area               square mile                km2               2.59
                      acre                    m2                4047
                      acre                  hectare              0.405
                   square yard                m2                0.836
                   square foot                m2                0.093
                   square inch                mm2               645.2

Volume              acre foot                 m3                1 23
                   cubic yard                 m3                0.765
                   cubic foot                 m3                0.028
                   cubic foot            L (1000 cm3)           28.32
                   gallon              L (1000 cm3)           3.785

Mass                   lb                      kg                0.454
                  

Force                  lb                       N                4.45
                       

Moment of mass          lb . ft               kg . m           0.138

Moment of inertia       lb . ft2              kg . m2         0.042

Power                ton (refrig)               kW             3.517
                        Btu/s                   kW             1.054
                     hp (electric)               W             745.7
                        Btu/h                    W             0.2931

Velocity, speed          ft/s                   m/s          0.305

Acceleration             f/s2                 m/s2           0.305

Momentum              lb . ft/sec            kg . m/s          0.138
----------

• One U.S. gallon of water weighs 8.34 pounds (U.S.) at 60 degrees F.
• One cubic foot of water weighs 62.4 pounds (U.S.).
• One milliliter of water has a mass of 1 gram and has a volume of one cubic centimeter.
• One part-per-million (PPM)
  • one inch in 16 miles
  • one minute in two years
  • one cent in $10,000
• One part-per-billion (PPB)
  • one 4-inch hamburger in a chain of hamburgers circling the earth at the equator 2.5 times
  • one second of time in 32 years
  • one sheet in a roll of toilet paper stretching from New York to London