Converting Metric Units

King Henry Drinks Much Dark Chocolate Milk

King Henry Likes Diamonds BUT Diamonds Cost Money

The order of prefixes in the metric system, for every power of ten from 3 to -3, is Kilometre, Hectometre, Decametre, Metre, Decimetre, Centimetre, Millimetre:

• King Hector's Daffy Mother Drinks Chocolate Milk
• King Henry's Daughter Makes Delicious Chocolate Muffins
• King Henry Died Monday Drinking Chocolate Milk
• King Henry Died! Mother Didn't Care Much
• King Hector Dector Makes Delicious Chocolate Milk
• Kangaroos Hop Down Mountains During Cold Months
• Kings Have Diamonds. Most Diamonds Cost Money.
• King Henry Died Monday During Christmas Mass.

This variant is for the prefixes Kilo-, Hecto-, Deca-, then the Base unit (such as metre, gram, litre), then the prefixes Deci-, Centi-, Milli-:

• Kings Have Diamonds But Diamonds Cost Money

The prefixes for powers of ten from 18 to -18 using increments of 3 are Exa- (18), Peta- (15), Tera- (12), Giga- (9), Mega- (6), Kilo- (3), unit (0), Milli- (-3), Micro- (-6), Nano- (-9), Pico- (-12), Femto- (-15), Atto- (-18):

• Exacting Petals, Terribly Gigantic Megaphones Killed 1 Million Microscopic Nasturtiums Picked Freshly by Attorneys.

A subset of the prefixes is Tera- (12), Giga- (9), Mega- (6), Micro- (-6), Nano- (-9), Pico- (-12), Femto- (-15), Atto- (-18):

• The Gooey Monster May Not Pick Five Apples. 

Source:  http://www.ict4us.com/r.kuijt/en_metricsystem.htm