Story Lengths

Flash fiction: 1-500 words
Short, short: 501-1,999 words
Short story: 2,000-7,499 words (though some magazines, ezines, etc. consider
4,999 the limit, instead of 7,499).
Novelettes: 7,500-24,999
Novellas: 25,000-49,999
Novels: 50,000 words and up (mainstream novels are almost always 80,000 words and up though)

Some places such as electronic publishers view the limits differently. One E-publisher considers a novella 15,000 words, which is considered easier on the eyes in shorter lengths.

250 words in Times New Roman or Courier 12-point are about the equivalent of one page in a published book.

I've found the following rough Writing.Com equivalents for story lengths. I say rough because the exact length depends on how many spaces in the story, how many paragraphs and exactly what punctuation is in the item. For example, quote marks translate to 5 spaces apiece here at Writing.Com. A story heavy in dialogue will take up more room than a story with lengthy paragraphs and no dialogue.

Flash fiction of 500 words or less - 3K
Short, short of less than 2,000 words - 12K
Short story of less than 7,500 words - 45K

I've found that a 50K contest or review limit translates to around 9,000 words.