Dry measure units commonly used in the USA include the bushel, the peck (0.25 bushels), the gallon (0.125 bushels), the quart (0.03125 bushels), the pint (0.01562 bushels), and the gill (0.003906 bushels).  A bushel is equivalent to 2150 cubic inches.

See also Metric Volume Unit Conversions.

Weight Conversion

Metric weight units include the gram, the kilogram (1,000 grams), the tonne (1,000,000 grams), the carat (0.2 grams), the centigram (0.01 grams), the milligram (0.001 grams), and the microgram (0.000001 grams).

Avoirdupois weight units commonly used in the USA include the pound, the stone (14 pounds), the short hundredweight (100 pounds), the short ton (2,000 pounds), the ounce (1/16th pound), the dram (1/256th pound), and the grain (1/7000th pound).
 

Metric "weight" units are, more correctly, known as "mass" units.  See also Metric Mass Unit Conversions.

Pressure Conversion

Metric pressure units include the bar, the millibar (0.001 bars), and the pascal (0.00001 bars).  One bar is equivalent to 10,200 kilograms per square meter.

The pressure units commonly used in the USA include the inch of mercury and the atmosphere (29.92 inches of mercury).  One atmosphere is equivalent to 14.7 pounds per square inch.

See also Metric Pressure Unit Conversions.

Energy Conversion

Metric energy units include the joule, the kilojoule (1000 joules), and the megajoule (1000000 joules).

The energy units commonly used in the USA include the calorie and the British Thermal Unit (BTU).  A calorie is commonly defined as the amount of heat energy required to raise the temperature of one gram of water by one degree Celsius.  However, the energy needed for this task depends on the water's starting temperature.  The thermochemical calorie is defined as exactly 4.184 joules, but several other, slightly different definitions exist as well.  One calorie is equivalent to 3.088 foot-pounds; one BTU is equivalent to 252 calories.  Using this latter definition, one calorie is equal to 4.187 joules.

See also Metric Energy Unit Conversions.

Temperature Conversion

Metric temperature units include degrees Celsius and degrees Kelvin (degrees Celsius plus 273.1).  At sea level, the freezing temperature of water is 0 degrees Celsius and the boiling point of water is 100 degrees Celsius.

The temperature unit commonly used in the USA is Fahrenheit.  At sea level, the freezing temperature of water is 32 degrees Fahrenheit and the boiling point of water is 212 degrees Fahrenheit.

See also Metric Temperature Unit Conversions.