Metric Prefixes and Unit Conversions

Metric Prefixes

• Yotta = 10²⁴  Symbol: Y
• Zeta = 10²¹  Symbol: Z
• Exa = 10¹⁸  Symbol: E
• Peta = 10¹⁵  Symbol: P
• Tera = 10¹²  Symbol: T
• Giga = 10⁹  Symbol: G
• Mega = 10⁶  Symbol: M
• Kilo = 10³  Symbol: k
• Hecto = 10²  Symbol: h
• Deca = 10¹  Symbol: da
• Deci = 10⁻¹  Symbol: d
• Centi = 10⁻²  Symbol: c
• Milli = 10⁻³  Symbol: m
• Micro = 10⁻⁶ Symbol: μ
• Nano = 10⁻⁹  Symbol: n
• Pico = 10⁻¹²  Symbol: p
• Femto = 10⁻¹⁵  Symbol: f
• Atto = 10⁻¹⁸  Symbol: a
• Zepto = 10⁻²¹  Symbol: z
• Yocto = 10⁻²⁴  Symbol: y

Unit Conversions

The below list shows conversions for different units.

Conversion factors for temperature

^oF = (^oC)(9/5) + 32
^oC = (^oF – 32)(5/9)
^oR = ^oF + 459.67
^oK = ^oC + 273.15

Conversion equivalencies for volume

1 US gallon (gal) = 231.0 cubic inches (in³) = 4 quarts (qt) = 8 pints (pt) = 128 fluid ounces (fl. oz.) = 3.7854 liters (l)

1 Imperial gallon (gal) = 160 fluid ounces (fl. oz.) = 4.546 liters (l)

1 milliliter (ml) = 1 cubic centimeter (cm³)

Conversion equivalencies for distance

1 inch (in) = 2.540000 centimeter (cm)

1 foot (ft) = 12 inches (in)

1 yard (yd) = 3 feet (ft)

1 mile (mi) = 5280 feet (ft)

Conversion equivalencies for velocity

1 mile per hour (mi/h) = 88 feet per minute (ft/m) = 1.46667 feet per second (ft/s) = 1.60934 kilometer per hour (km/h) = 0.44704 meter per second (m/s) = 0.868976 knot (knot—international)

Conversion equivalencies for weight

1 pound (lb) = 16 ounces (oz) = 0.45359 kilogram (kg)

Conversion equivalencies for force

1 pound-force (lbf) = 4.44822 newton (N)

Conversion equivalencies for area

1 acre = 43560 square feet (ft²) = 4840 square yards (yd²) = 4046.86 square meters (m²)

Conversion equivalencies for pressure

1 pound per square inch (psi) = 2.03603 inches of mercury (in. Hg) = 27.6807 inches of water (in. W.C.) = 6894.757 pascals (Pa) = 0.0680460 atmospheres (Atm) = 0.0689476 bar (bar)

Conversion equivalencies for energy or work

1 british thermal unit (BTU—“International Table”) = 251.996 calories (cal—“International Table”) = 1055.06 joules (J) = 1055.06 watt-seconds (W-s) = 0.293071 watt-hour (W-hr) = 1.05506 x 10¹⁰ ergs (erg) = 778.169 foot-pound-force (ft-lbf)

Conversion equivalencies for power

1 horsepower (hp—550 ft-lbf/s) = 745.7 watts (W) = 2544.43 british thermal units per hour (BTU/hr) = 0.0760181 boiler horsepower (hp—boiler)

Acceleration of gravity (free fall), Earth standard

9.806650 meters per second per second (m/s²) = 32.1740 feet per second per second (ft/s²)

Physical constants

Speed of light in a vacuum (c) = 2.9979 × 10⁸ meters per second (m/s) = 186,281 miles per second (mi/s)

Avogadro’s number (N_A) = 6.022 × 10²³ per mole (mol⁻¹)

Electronic charge (e) = 1.602 × 10⁻¹9 Coulomb (C)

Boltzmann’s constant (k) = 1.38 × 10⁻²³ Joules per Kelvin (J/K)

Stefan-Boltzmann constant (σ) = 5.67 × 10⁻⁸ Watts per square meter-Kelvin⁴ (W/m²·K⁴)

Molar gas constant (R) = 8.314 Joules per mole-Kelvin (J/mol-K)

Properties of Water

Freezing point at sea level = 32^oF = 0^oC

Boiling point at sea level = 212^oF = 100^oC

Density of water at 4^oC = 1000 kg/m³ = 1 g/cm³ = 1 kg/liter = 62.428 lb/ft³ = 1.94 slugs/ft³

Specific heat of water at 14^oC = 1.00002 calories/g·^oC = 1 BTU/lb·^oF = 4.1869 Joules/g·^oC

Specific heat of ice ≈ 0.5 calories/g·^oC

Specific heat of steam ≈ 0.48 calories/g·^oC

Absolute viscosity of water at 20^oC = 1.0019 centipoise (cp) = 0.0010019 Pascal-seconds (Pa·s)

Surface tension of water (in contact with air) at 18^oC = 73.05 dynes/cm

pH of pure water at 25^o C = 7.0 (pH scale = 0 to 14)

Properties of Dry Air at sea level

Density of dry air at 20^oC and 760 torr = 1.204 mg/cm³ = 1.204 kg/m³ = 0.075 lb/ft³ = 0.00235 slugs/ft³

Absolute viscosity of dry air at 20^oC and 760 torr = 0.018 centipoise (cp) = 1.8 × 10⁻⁵ Pascal-seconds (Pa·s)