Periods

Follow these guidelines for periods.

Acronyms and Abbreviations

Don't use periods with most acronyms or abbreviations for technical terms, standard nontechnical abbreviations, or abbreviations for units of measure:
- ANSI (acronym)
- MB (technical abbreviation)
- PhD (nontechnical abbreviation)
- ft (unit of measure)
If the abbreviation forms a word, such as in as an abbreviation for inches, spell out the word in text to avoid confusing the reader. Confine use of the abbreviation to tabular matter and other condensed copy.
For time values in a twelve-hour system, use AM/PM preceded by a space. For example, 10:30 PM. Don’t use a.m., p.m., A.M., P.M., am, or pm.

When the quoted material is at the end of the sentence or in a series, including the period or comma in quotation marks can confuse the user. In this case, reword the sentence. If this isn't possible, place the period or comma outside the quotation marks.
When parentheses or brackets enclose an independent sentence, place the period or comma inside. Otherwise, place the period or comma outside.
Omit the period after items in a bulleted or other type of list only if the items are fragments rather than complete sentences. However, a period is necessary at the end of a sentence whenever more than one sentence exists for that bullet. In this case, make all bullets complete sentences that end in periods so that each bullet is parallel.