Commas are such an everyday part of punctuation that, most of the time, we use them without thinking. We did exactly that when writing the previous sentence, for instance.\n\n[caption id="attachment_2262" align="aligncenter" width="350"] These little fellas.[\/caption]\n\nHowever, there are formal rules for how commas should be used. In academic writing, these can help you know when a comma is required, so try to keep them in mind while working.\nThe Rules for Commas\nWe can\u2019t list every rule for comma use here, unfortunately, since there are too many to fit in just one blog post. Nevertheless, some of the most important are as follows.\n\n 1. Separating Independent Clauses Joined by a Conjunction\n\nIndependent clauses are statements that could work as a standalone sentence. If joining two of these with a coordinating conjunction (i.e. and, but, for, or, nor, so or yet), the conjunction should be preceded by a comma:\nI use commas, but I avoid semicolons.\n 2. After Introductory Words, Clauses and Phrases\n\nUse a comma when the main clause in a sentence is preceded by additional information:\nOver the last century, comma butterfly numbers have decreased.\n\n\n[caption id="attachment_2263" align="aligncenter" width="376"] Named after the little white mark on its underwing, in case you were wondering.[\/caption]\n\n 3. Parenthetical Commas\n\nCommas can also be used to set off a clause that adds information, but which isn\u2019t essential to a sentence:\nCommas, although common in written English, are frequently misused.\n 4. Separating Items in a List\n\nIn a list of three or more things, items should be separated with commas. This isn\u2019t always necessary before the final item, but adding an \u2018Oxford comma\u2019 can aid clarity:\nPopular pets include dogs, cats, and hamsters.\n 5. Separating Coordinate Adjectives\n\nAdjectives are coordinate when their order could be changed without altering the meaning of the sentence (e.g. \u2018a charming, intelligent man\u2019).\n\nNo comma is required when the adjectives preceding a noun aren't coordinate, which means their order can't be changed without it sounding strange (e.g. \u2018a big bad wolf\u2019).\n\nTry placing \u2018and\u2019 between adjectives to see if they are coordinate (e.g. \u2018a charming and intelligent man\u2019 is OK, but \u2018a big and bad wolf\u2019 would sound unusual).\n\n[caption id="attachment_2264" align="aligncenter" width="372"] 'Oh my, Grandma! How big and bad you look today!'[\/caption]\n\n 6. Introducing Quoted Material\n\nIf quoted text follows from the rest of a sentence, use a comma to introduce it:\nJones writes, \u2018Commas are troublesome punctuation marks.\u2019\nThis is not necessary if the quote is preceded by \u2018that\u2019:\nJones writes that \u2018[c]ommas are troublesome punctuation marks\u2019.\n 7. Setting Apart a Contrast\n\n\nWhen introducing a contrast at the end of a sentence, a comma precedes the new clause:\nThis sentence uses a comma, not a semicolon.\n8. Direct Address Commas\nWhen a sentence is addressed to someone, you can say who either before or after a comma:\nBefore: Billy, let's go eat!\nAfter: Let's go eat, Billy!\nThis comma can be very important. For example, while 'Let's go eat, Billy!' is an invitation for Billy to join you for dinner, 'Let's go eat Billy!' would be an invitation to eat Billy.\n\n\n[caption id="attachment_2265" align="aligncenter" width="350"] When a misplaced comma leads to cannibalism, you're having a very bad day.[\/caption]\nBreaking the Rules\nAs with many \u2018rules\u2019 in English, these notes on comma use are actually just guidelines.\n\nThis is important, because adding too many commas to a sentence can make it tricky to read. Consequently, you should always consider the context when deciding whether or not to use a comma, since clarity is usually more important than sticking to the rules.