Examples:

• 1 MB (MegaByte) = 1,024 KB (KiloBytes) = 1,048,576 Bytes = 8,388,608 bits =~ one million Bytes
  "One megabyte ... is equal to eight million, three hundred eighty-eight thousand, six hundred and eight bits, (which) is approximately equal to one million bytes."
• 1 GB =~ 1 Billion Bytes (1 GB = 1,073,741,824 Bytes)
  "One gigabyte is approximatley equal to one billion bytes... ."

The preferred way of symbolizing "approximately equal to" is to use the ≅ symbol, the ≈ symbol, or the ~ symbol. However:
• ≅ and ≈ are not easy for people to enter in email, forums, etc. (no standard keyboard entry method)
• ≅ and ≈ are not universally rendered correctly in web browsers (you may be looking at boxes instead of symbols right now) and are not commonly parsed correctly in things like commenting tools and forums
• the ~ symbol is too often to indicate some other meaning (or decoratively). (In HTML 4 "~" is defined as "varies with" or "similar to".)

"=~" is an easy to use and remember alternative.

~= is a possible expansion of ≅

Note: technically, "approximately equal to, U+2245" is defined in HTML 4 as "cong" (≅ ≅), but this symbol has very limited support and rarely renders correctly in web browsers. (Furthermore, it is not widely recognized by most people.)

If text can be entered as HTML, you can also use the following notations:

•  (=~) ( =~ )
• ≈ (≈)
• ≈ ( ≈ ) [Decimal NCR notation]

* email, comment forms, forums, message boards, et cetera