Rules on Punctuation

I. Spacing With Punctuation Marks

Do Not Type a Space ...

following a period with an abbreviation
following a period used as a decimal point
between quotation marks and the quoted material
before or after a hyphen
before or after a slash
before or after a dash
between a number and percent sign
between parentheses and the enclosed material
between any word and the punctuation following it.
between the number and the colon used to indicate a dilute solution or ratio.
on either side of the colon when expressing the time of day
before an apostrophe
before or after a comma used within numbers
before or after an ampersand in abbreviations, e.g., C&S
on either side of the colon when expressing ratios e.g. 1:1
after the closing parenthesis if another mark of punctuation follows

Type One Space...

between words
after a comma
after a semicolon
after a period following an initial
after the closing parenthesis
on each side of the x in an expression of dimension, e.g. 4 x 4

Type Two Spaces...

after punctuation at the end of a sentence
after a colon except when expressing time or a dilution ratio