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Smart quotes and proper apostrophes are always curvy or sloped. Single quotes should be used inside of double quotes (in American English).

How can I tell if I’m using smart quotes or dumb quotes? Smart quotes (also known as curly quotes, typographer’s quotes or proper quotation marks) are either curved or sloped. Dumb quotes (also known as straight quotes) are straight and vertical. The design of smart quotes will vary between serif and sans-serif typefaces, but they will never point straight up-and-down.

When is it appropriate to use straight quotes? Proper typography never uses straight quotes. They are known as dumb quotes, and I’m guessing you don’t want to look dumb. They are left over from the age of typewriters, and their only modern use is for coding.

When typing an email, is it ok to use straight quotes? I personally think it’s acceptable to use straight quotes when typing emails. It can be difficult to constantly type proper apostrophes (especially on a mobile device), and there is always a chance the recipient’s email client won’t display them correctly anyway.

Are prime symbols the same as straight quotes? No. Prime symbols are an entirely different punctuation mark than either straight quotes or smart quotes. They are used for measurements, such as feet and inches or minutes and seconds. See the useful typographic characters table for more info.

What’s the difference between an apostrophe and a closing single quote? There is no difference—they are exactly the same character. The same rules for smart quotes apply to apostrophes as well—make sure your apostrophes are curved or sloped and not straight up-and-down.

When is it grammatically correct to use an apostrophe? Apostrophes should be used for contractions (I’m, you’re, ’89) and to show possession (Homer’s beer, the dog’s toy). There are also a few instances when it is correct to use an apostrophe to form a plural, such as dot your i’s and cross your t’s and yes’s and no’s. For more detailed grammar rules, see this page.

When should it’s contain an apostrophe? The only time it’s should have an apostrophe is when it replaces it is or it has. The possessive form of its should not contain an apostrophe, just like possessive pronouns such as hers don’t require apostrophes.

Should punctuation be placed inside or outside of quotation marks? In American English, periods and commas should always go inside quotation marks. In British English, unquoted periods and commas are placed outside quotation marks. For all other punctuation, American and British English have the same rule—if the punctuation isn’t directly part of the original quotation, then it should go outside the quotation marks.

When should I capitalize the first letter within a quote? Always capitalize the first letter of a quote if the quote is a complete sentence. If the quoted material is a sentence fragment, then don’t capitalize the first letter. The exception to these two rules is if the quote is interrupted in the middle of a sentence—in that case, do not capitalize the second part of the quote.

When should I use a single quote versus a double quote? In American English, single quotes are used for quotes inside of quotes. In British English, this is usually reversed. Newspaper headlines may also use single quotes in place of double quotes to save space.

Should I use quotes for emphasis? No. Always use italics or bold for emphasis—unless you want to end up on The “Blog” of “Unnecessary” Quotation Marks.

How do I type these characters on my keyboard? On Windows, hold down the alt key while typing the four-digit code on your nu­meric key­pad with num lock activated. On a Mac, press the specified keys simultaneously.

What’s the best way to use smart quotes and apostrophes on my website? If your site uses the UTF -8 charset, then you can use the keyboard shortcuts in the table above (or just copy and paste them). Manually inputting the HTML entities works fine as well. However, a much easier solution is to set up your CMS to automatically convert your straight quotes into the correct HTML entities.

For the HTML entities, should I use entity names like “‘” or entity numbers like “‘”? I recommend using entity names. They are easier to remember and make for clearer code. Entity numbers have slightly wider browser support, but not enough to make any meaningful difference in this day and age.