Is it K or M when referring to "per thousand"?

Have you noticed.... that the print / mailing / marketing services world uses "M" in their pricing quotes while the financial world uses "K" and each one means "per thousand?

In the marketing and data world, "M"  stands for per thousand records of data. In the print world, it would stand for per thousand sheets of paper, or other print functions like inserting, or completed print pieces. Many manufacturers also use "M" in their per unit pricing.

M and MM are Roman numerals where M stands for "one thousand" and MM is intended to denote "one thousand thousands"or "one million". A quote for mailing services would commonly show as \$ /M.  For example, a cost quoted as \$25/M would equate to \$25 for every thousand pieces. It has its roots in the British Imperial System using Roman numerals and can also be referred to as USCS (US Customary System).

CPM - Cost Per Thousand  (M=1,000) - is a marketing advertising term referring to the cost usually referred to for internet pricing. For example - the cost of a Google or Facebook ad might show as \$10 CPM, meaning \$10 for every thousand times your ad appears. CPC means "cost per click".

The financial world uses "K" when referring to "per thousand dollars". Why is there such a difference in terms when they basically mean the same thing?

K comes from the Greek world "kilo" which means one thousand and is used in metric / decimal systems. The corresponding prefix for one million is M. An amount in the accounting and financial world shown as \$14K would equate to \$14,000.00.

It is entirely possible when dealing with a vendor that both terms could be used in the same sentence:  An example would be a marketing quote for 80,000 records of data for a list order or pertaining to a large print order:

\$45/M x 80 = \$3.6k (\$3,600.00)

One answer I came across as to why industry uses USCS and not metric is that when the industrial revolution happened, measurements were based on the imperial system and as time went on, it was too cost prohibitive to change. Industries dealing with international business would likely use metric.

Otherwise, I can't really find an answer as to why these two professions use different ways of of expressing "per thousand". Trust me though -- it makes a big difference when talking with various vendors for services. It's good to understand that these differences exist.

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