Appendix C: Units and Conversion Factors
Units of Length, Mass, Energy & Pressure
Unit  Equivalent Units 

meter (m)  = 39.37 inches (in.)
= 1.094 yards (yd)

centimeter (cm)  = 0.01 m (exact, definition) 
millimeter (mm)  = 0.001 m (exact, definition) 
kilometer (km)  = 1000 m (exact, definition) 
angstrom (Å)  = 10^{–8} cm (exact, definition)
= 10^{–10} m (exact, definition)

yard (yd)  = 0.9144 m 
inch (in.)  = 2.54 cm (exact, definition) 
mile (US)  = 1.60934 km 
Unit  Equivalent Units 

liter (L)  = 0.001 m^{3} (exact, definition)
= 1000 cm^{3} (exact, definition) = 1.057 (US) quarts

milliliter (mL)  = 0.001 L (exact, definition)
= 1 cm^{3} (exact, definition)

microliter (μL)(μL)  = 10^{–6} L (exact, definition)
= 10^{–3} cm^{3} (exact, definition)

liquid quart (US)  = 32 (US) liquid ounces (exact, definition)
= 0.25 (US) gallon (exact, definition) = 0.9463 L

dry quart  = 1.1012 L 
cubic foot (US)  = 28.316 L 
Unit  Equivalent Units 

gram (g)  = 0.001 kg (exact, definition) 
milligram (mg)  = 0.001 g (exact, definition) 
kilogram (kg)  = 1000 g (exact, definition)
= 2.205 lb

ton (metric)  =1000 kg (exact, definition)
= 2204.62 lb

ounce (oz) (avoirdupois)  = 28.35 g 
pound (lb) (avoirdupois)  = 0.4535924 kg 
ton (short)  =2000 lb (exact, definition)
= 907.185 kg

ton (long)  = 2240 lb (exact, definition)
= 1.016 metric ton

Unit  Equivalent Units 

4.184 joule (J)  = 1 thermochemical calorie (cal) 
1 thermochemical calorie (cal)  = 4.184 × 10^{7 } erg 
erg  = 10^{–7} J (exact, definition) 
electronvolt (eV)  = 1.60218 × 10^{−19} J = 23.061 kcal mol^{−1} 
liter∙atmosphere  = 24.217 cal = 101.325 J (exact, definition) 
nutritional calorie (Cal)  = 1000 cal (exact, definition) = 4184 J 
British thermal unit (BTU)  = 1054.804 J^{[1]} 
Unit  Equivalent Units 

torr  = 1 mm Hg (exact, definition) 
pascal (Pa)  = N m^{–2} (exact, definition)
= kg m^{–1} s^{–2} (exact, definition)

atmosphere (atm)  = 760 mm Hg (exact, definition)
= 760 torr (exact, definition) = 101,325 N m^{–2} (exact, definition) = 101,325 Pa (exact, definition)

bar  = 10^{5} Pa (exact, definition)
= 10^{5} kg m^{–1} s^{–2} (exact, definition)

Attribution & References
Except where otherwise noted, this page is adapted from “Appendix C: Units and Conversion Factors” In General Chemistry 1 & 2 by Rice University, a derivative of Chemistry (Open Stax) by Paul Flowers, Klaus Theopold, Richard Langley & William R. Robinson and is licensed under CC BY 4.0. Access for free at Chemistry (OpenStax)
 BTU is the amount of energy needed to heat one pound of water by one degree Fahrenheit. Therefore, the exact relationship of BTU to joules and other energy units depends on the temperature at which BTU is measured. 59 °F (15 °C) is the most widely used reference temperature for BTU definition in the United States. At this temperature, the conversion factor is the one provided in this table. ↵