 

Examples  

From  Result  
foot  0.3048 meters  
83 degF  28.333333333 degreesCelsius  
(6 * 18) mile^2  279.71871592 kilometers^2  
70.4 kg + 115 lb  122.56312255 kilograms  
(20ft + 2in) * (15ft  8in)  26.85413984 meters^2  
16.2 + sqrt(16.2^2  4 * 3.1 * 0.7)  0.27015379861  
(5 qt + 2 gal) / 4.751 seconds 
2.5894734368 liters / second  
pi (4.7 cm)^2 sin(41 deg)  45.529041288 centimeters^2  
50 meters * 25 meters * 10 ft  3810 meters^3  
(2000 V/m) * 35 cm * 2 elementarycharges  224.30470818 attojoules 
This calculator converts the "From" entry to the International System of Units (SI units) which is commonly called the metric system. The algorithm tries base, derived, and accepted metric units when seeking a concise metric equivalent. There are multiple ways to express a value in metric units, so the units returned here may not be in the form that you need.
Enter the units or the mathematical expression with units that you want to convert. This can be as simple as a unit name or as complex as a formula involving additions, subtractions, multiplications, divisions, powers, square roots, and scientific functions (sin, cos, tan, arcsin, arccos, arctan, sinh, cosh, tanh, log, ln, and exp). The expression entry is very flexible; try typing an expression as you would normally write it.
Expression Features  

Feature  Example  Interpretation  
Abbreviations are supported (see the name index).  ft  foot  
m  meter  
Standard metric power prefixes are supported.  millisecond  0.001 seconds  
kilometer  1000 meters  
Scientific notation is supported  4.2 * 10^3 
0.0042  
4.2e3  0.0042  
2 * 10^3  2000  
2e3  2000  
"^" is the power operator.  4^2  16  
mile^2  mile mile  
second^1  1 / second  
sqrt is the square root function.  sqrt(4 m^2)  2 meters  
sqrt(37)  (not supported)  
sin, cos, tan, arcsin, arccos, arctan, sinh, cosh, tanh, log, ln, and exp represent their respective scientific functions. A trig function argument without units is considered to be in radians but you can also use units such as deg with function arguments.  cos(pi/3)  0.5  
cos((pi/3) rad)  0.5  
cos(60 deg)  0.5  
sin(100 grad)  1.0  
tan(800 mil) 
1.0  
"*" or a space between expressions represents the multiply operator. However, if the expressions are simple and have the same dimensions, a space is treated as an addition (which is common with written expressions). 
(4 * 5) grams  20 grams  
3 newtons * 2 meters  6 newton meters  
5ft 45lbf  225 foot poundsforce  
6ft 4in  6 feet + 4 inches  
2hr 37min  2 hours + 37 minutes  
Modifiers square, sq, squared, cubic, cu, cubed, and reciprocal have their normal meaning.  square meter  meter^2  
sq yard  yard^2  
second squared  second^2  
cubic inch  inch^3  
cu yd  yard^3  
cm cubed  centimeter^3  
reciprocal second  1 / second  
In general, a "" connecting names is treated the same as a space. If you need a subtraction operator or negative sign involving just unit names, put at least one space around the "".  kilogrammeter/second^2  kilogram meter/second^2  
kg  lb  (subtraction)  
cubicyard 
yard^3  
cubic yard  (yard)^3  
Sometimes a "" is used to distinguish a unit name from an expression with the same words.  kilogramcalorie  the unit kilocalorie  
kilogram calorie  a mass times an energy 