Metric Conversions






Below are the factors for converting between SI units and some non-SI units commonly used in the U.S. A large number of other conversion factors exist, far too many to list here. See Appendix B of the NIST Special Publication 811, Guide for the Use of the International System of Units (SI). Factors in bold are exact. All other factors have been rounded to the significant digits given.

 To convert from  To  Multiply by
 ampere hour (A·h)  coulomb (C)  3.6 E+03
 astronomical unit (ua)  meter (m) 1.495 979 E+11
 circular mil  square meter (m2) 5.067 075 E-10
 cubic foot (ft3)  cubic meter (m3) 2.831 685 E-02
 cubic inch (in3)  cubic meter (m3) 1.638 706 E-05
 cup (U.S.)  liter (L) 2.365 882 E-01
 day (d)  second (s) 8.64 E+04
 degree (angle) (o)  radian (rad) 1.745 329 E-02
 degree Celsius (temperature) (oC)  kelvin (K) T /K = t /oC + 273.15
 degree Fahrenheit (temperature) (ºF)  degree Celsius (ºC)  t / º C = (t / º F - 32)/1.8
 fluid ounce (U.S.) (fl oz)  cubic meter (m3) 2.957 353 E-05
 fluid ounce (U.S.) (fl oz)  milliliter (mL) 2.957 353 E+01
 foot (ft)  meter (m) 3.048 E-01
 gallon (U.S.) (gal)  cubic meter (m3) 3.785 412 E-03
 gallon (U.S.) (gal)  liter (L)  3.785 412 E+00
 horsepower (550 ft · lbf / s) (hp)  watt (W) 7.456 999 E+02
 horsepower (electric)  watt (W) 7.46 E+02
 hour (h)  second (s) 3.6 E+03
 inch (in)  meter (m) 2.54 E-02
 inch (in)  centimeter (cm)  2.54 E+00
 kelvin (K)  degree Celsius (ºC) t / ºC = T / K - 273.15
 kilometer per hour (km / h)  meter per second (m / s) 2.777 778 E-01
 kilowatt hour (kW · h)  joule (J) 3.6 E+06
 knot (nautical mile per hour)  meter per second (m / s) 5.144 444 E-01
 light year (l.y.)  meter (m)  9.460 73 E+15
 liter (L)  (cubic decimeter)
 cubic meter (m3) 1.0 E-03
 lumen per square foot (lm / ft2)  lux (lx) 1.076 391 E+01
 micron (µ)  micrometer (µm) 1.0 E+00
 mil (0.001 in)  millimeter (mm) 2.54 E-02
 mile (mi)  kilometer (km)  1.609 344 E+00
 mile, nautical  meter (m) 1.852 E+03
 mile per gallon (U.S.) (mpg) (mi / gal)  kilometer per liter (km / L) 4.251 437 E-01
 mile per gallon (U.S.) (mpg) (mi / gal)  liter per 100 kilometer (L / 100 km) divide 235.215 by number of miles per gallon
 mile per hour (mi / h)  kilometer per hour (km / h) 1.609 344 E+00
 minute (angle) (')  radian (rad) 2.908 882 E-04
 minute (min)  second (s) 6.0 E+01
 ounce (avoirdupois) (oz)  gram (g) 2.834 952 E+01
 ounce (U.S. fluid) (fl oz)  cubic meter (m3) 2.957 353 E-05
 ounce (U.S. fluid) (fl oz)  milliliter (mL) 2.957 353 E+01
 pint (U.S. dry) (dry pt)  liter (L) 5.506 105 E-01
 pint (U.S. liquid) (liq pt)  liter (L) 4.731 765 E-01
 pound (avoirdupois) (lb)  kilogram (kg) 4.535 923 7 E-01
 pound-force (lbf)  newton (N) 4.448 221 615 260 5 E+00
 pound per square inch (not pound-force) (lb / in2)
 kilogram per square meter (kg / m2) 7.030 696 E+02
 psi (pound-force per square inch) (lbf / in2)  pascal (Pa)  6.894 757 E+03
 quart (U.S. dry) (dry qt)  liter (L) 1.101 221 E+00
 quart (U.S. liquid) (liq qt)  liter (L) 9.463 529 E-01
 revolution per minute (rpm) (r / min)  radian per second (rad / s) 1.047 198 E-01
 second (angle) (")  radian (rad) 4.848 137 E-06
 square foot (ft2)  square meter (m2) 9.290 304 E-02
 square inch (in2)  square centimeter (cm2) 6.4516 E+00
 square mile (mi2)  square kilometer (km2) 2.589 988 E+00
 square yard (yd2)  square meter (m2) 8.361 274 E-01
 tablespoon  milliliter (mL) 1.478 676 E+01
 teaspoon  milliliter (mL) 4.928 922 E+00
 tonne (called “metric ton” in U.S.) (t)  kilogram (kg) 1.0 E+03
 ton, short (2000 lb)  kilogram (kg) 9.071 847 E+02
 watt hour (W · h)  joule (J) 3.6 E+03
 yard (yd)  meter (m) 9.144 E-01
 year (365 days)  second (s)  3.1536 E+07