"Email" or "e-mail"?

Which way of writing the word: "Email" or "e-mail" is correct? Both variants seem to be in wide use. If both ones are okay, maybe there is a difference in contexts they have been used (one is more formal than the other)?

Both e-mail and email are in standard use at this point, although e-mail retains a vast majority of usage in edited, published writing according to my research using the Corpus of Contemporary American English (COCA).

Here are the current results counts in COCA for various categories of English:

Obviously the “spoken” totals don’t represent any kind of actual usage but rather the policies of the organizations that transcribed the spoken data, so I also included a total that excludes the spoken examples. So, in (edited, published) fiction, magazines, newspapers, and academic writing we find that the traditional e-mail outnumbers incidences of email by more than 8.5 to 1. COCA includes data starting from 1990.

Now that we have established that e-mail retains the position of preferred usage by a very large margin, let’s look at trends over time. These numbers are in incidences per million words (rather than total incidences):

This is a graphical representation showing the data over time:

The blue and red lines show the frequency of incidence for e-mail and email per million words. The orange line shows the ratio of incidence between e-mail and email over the same period. From these results, we see that e-mail was on a meteoric rise in the 1990s and by 2000 it has locked in at between 70 and 100 incidences per million words. Email, on the other hand, saw very little usage until 2005, when its use soared up to about 30 incidences per million words over the last few years.

What does all this tell us? We see a word whose spelling is in transition. It is not clear whether email will eventually reach and surpass e-mail. For the time being, e-mail has retained its position as the preferred usage by a factor of three to one over the past few years. The numbers can change very quickly and email may win out in five years, or it may stay a minority usage for a long time. Only time will tell. In the meantime, you are in good company if you use e-mail. That’s what I use.

Edit March 8, 2012:

I created a Google N-gram which compares instances of e-mail with email in the Google Books corpus between 1988 and 2008, and it does seem that e-mail hit a peak around 2004, and has been in decline since, though it remains significantly more common than email.

Curiously, when you look in the country-specific corpora, you find that the gap is wider in American English and narrower in British English:

American English

British English

Both are correct and common. I'd recommend the shorter and simpler email.

There seems to be a tendency to drop hyphen as a newly coined word becomes more and more commonplace:

electronic mail → e-mail → email

That is what I've read earlier somewhere, and looking around I now found at least this quote by Donald Knuth to support the claim:

Newly coined nonce words of English are often spelled with a hyphen, but the hyphen disappears when the words become widely used. For example, people used to write "non-zero" and "soft-ware" instead of "nonzero" and "software"; the same trend has occurred for hundreds of other words. Thus it's high time for everybody to stop using the archaic spelling "e-mail". Think of how many keystrokes you will save in your lifetime if you stop now! The form "email" has been well established in England for several years, so I am amazed to see Americans being overly conservative in this regard.

Even if you ignore that, overwhelming evidence seems to suggest that "email" is the form that everyone is likely to eventually settle upon (so you might just as well go with that now):

• Most dictionaries use "email"; see the "Spelling" section in Wikipedia's Email article
  • Do also note the title of that article...
• This note on the Wikipedia talk page points out that "email" is used almost unanimously by both email web service providers and client software authors, Microsoft being a lone proponent of "e-mail".
  • More recently even Microsoft seems to have given in (partially)! Although Outlook is still called an "e-mail" management tool, Hotmail now claims to be The efficient way to do email.

That said, if you deliberately want to sound ultra-formal or ceremonial, go with "electronic mail". :-)

I generally use "email". I think people who work with technology use "email" and people who write about it use "e-mail" (though this isn't a standard).

Google, Yahoo and Apple use "email". USAToday, CNN and the New York Times use "e-mail".

According to wikipedia: There are several spelling variations that occasionally prove cause for surprisingly vehement disagreement.

• email is the form required by IETF Requests for Comment and working groups. This spelling also appears in most dictionaries.
• e-mail is a form recommended by some prominent journalistic and technical style guides.

Read more on: Email