The following is a listing of the root conversion factors (and formulas, as necessary):

inches to millimeters: × 25.4

inches to centimeters: × 2.54

feet to centimeters: × 30.48

feet to meters: × 0.3048

yards to meters: × 0.9144

miles to kilometers: × 1.609344

℉ to ℃: (℉ - 32) ÷ 1.8

℃ to ℉: (℃ × 1.8) + 32

teaspoons to milliliters*: × 4.92892159

tablespoons to milliliters: × 14.7867648

fluid ounces to milliliters: × 29.5735296

cups to milliliters: × 236.588237

pints to liters*: × 0.473176473

pounds to kilograms**: × 0.45359237

ounces to grams: × 28.3495231

gallons to liters: × 3.78541178

MPG to l/100km: (1/MPG) × 235.21458

(Imperial MPG: US MPG × 1.20095042 (based on larger Imperial gallon)

  g CO2/km based on CO2 concentrations of 2.315kg/l for gasoline and 2.63kg/l for diesel)

HP to kW: x 0.745699872

lb∙ft to N∙m: x 1.355818

Notes:    * liter and litre are both common spellings for this metric unit of volume.

              ** technically this conversion compares force to mass, but it is practical.