Useful Conversion Factors

Conversion Factors and Constants

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You may find these conversion factors (and constants!) useful at some point during the year on worksheets, for projects, or during labs.

We typically use metric units for everything, but there may be a time when you are asked/required to convert from an English measurement (inches, miles, pounds, etc.) to an appropriate metric equivalent.

	Metric Prefixes
	Mass and Force
	Length, area, and volume

	Energy
	Miscellaneous constants

Metric Prefixes:

Prefix	Symbol	Multiplier*	Exponent (order of magnitude)
exa-	E	1 000 000 000 000 000 000	10¹⁸
peta-	P	1 000 000 000 000 000	10¹⁵
tera-	T	1 000 000 000 000	10¹²
giga-	G	1 000 000 000	10⁹
mega-	M	1 000 000	10⁶
kilo-	k	1 000	10³
hecto-	h	100	10²
deca-	da	10	10¹
deci-	d	0.1	10^-1
centi-	c	0.01	10^-2
milli-	m	0.001	10^-3
micro-	m	0.000 001	10^-6
nano-	n	0.000 000 001	10^-9
pico-	p	0.000 000 000 001	10^-12
femto-	f	0.000 000 000 000 001	10^-15 `
atto-	a	0.000 000 000 000 000 001	10^-18

*note: "Multiplier" means that this is the number of base units in 1 unit with that prefix. Essentially, it is the definition of the prefix

For example: 1 GW (gigawatt) is equal to 1 000 000 000 Watts

Mass and Force

	1 kilogram (kg) = 2.20462 pounds (lb) (mass)
	1 pound (lb) = 4.44822 Newtons (N) ( note: Newtons are a force, kilograms are a mass)*
	1 pound (lb) = 16 ounces (oz)
	1 pound (lb) = 453.592 grams (g)
	1 gram (g) = 5 carat (ct)

Length, Area, and Volume

	1 nautical mile (nmi) = 1.15078 statute mile (mi) ("normal" land mile)
	1 mile (statute) (mi) = 1.609344 kilometer (km)
	1 parsec (pc) = 3.2616 lightyears (ly)
	1 lightyear (ly) = 63 240 astronomical unit (AU)
	1 astronomical unit (AU) = 1.49598 x 10⁸ kilometers (km)
	1 inch (in) = 2.54 centimeter (cm)
	1 yard (yd) = 3 feet (ft)
	1 nanometer (nm) = 10 angstrom (Å)
	1 cubic decimeter (dm³) = 1 Liter (L)
	1 gallon (gal) = 3.7854 Liters (L)
	1 gallon (gal) = 4 quart (qt)
	1 quart (qt) = 2 pints (pt)
	1 pint (pt) = 2 cup
	1 hectare (ha) = 2.47105 acre
	1 square kilometer (km²) = 100 hectare (ha)
	1 cubic centimeter (cm³) = 1 milliliter (mL)

Energy

	1 kiloton TNT = 1 terajoule (TJ)
	1 gigajoule (GJ) = 277.778 kilowatt-hour (kWh)
	1 Megaelectronvolt (MeV) = 160 218 attojoule (aJ)
	1 attojoule (aJ) = 6.24151 electronvolt (eV)
	1 Megajoule (MJ) = 239.006 kilocalorie (kcal)
	1 British Thermal Unit (BTU) = 1.05435 kilojoules (kJ)
	1 kilojoule (kJ) = 239.006 calorie (cal) (thermochemical calorie)
	1 calorie (dietetic) = 4.1855 kilojoule (kJ)

Some Miscellaneous constants:

Avogadro's constant (N_A) = 6.022 x 10²³ mol^-1

Charge on an electron (- e) = 1.602 x 10^-19 C

Electron rest mass (m_e) = 9.1094 x 10^-31 kg

Molar gas constant (R) = 8.3145 J·mol^-1·K^-1

Newton's Gravitational constant (G) = 6.67259 x 10^-11 m³·kg^-1·s^-2

Planck constant (h) = 6.62608x 10^-34 J·s

Planck constant/2p {(h/2p)=ħ} = 1.05457 x 10^-34 J·s

Stefan-Boltzmann constant (σ) = 5.67051 x 10^-8 W·K^-4·m^-2

Speed of light (in a vacuum) = 299 792 458 m·s^-1 = 3.00x 10⁸ m·s^-1