You only have a split second to grab someone’s attention with an email. Here are some ideas for what to put in your email subject line to increase the chances of it getting opened and read.

We get a lot of emails and, for many people, ignoring a lot of them or deleting them unopened is simply a survival tactic. There are not enough hours in a day to read everything.

This is why what you write in your subject line when sending an email matters when you’re applying for a job or trying to make a professional connection. You want the recipient to read that line and be driven to open the email.

How do you do that? Here are some tips that can help you get your email read and avoid getting it deleted or ignored.

Don’t forget the subject line

Blank is bad, particularly when in a professional situation. We’ve all accidentally sent emails with no subject line, and then we wonder if we should re-send with a subject line or just leave it alone and hope for the best. Get it right the first time and be sure to include the subject line.

If there are instructions, follow them

Often, a job posting will have specific instructions like, “Send your application to maria@thisemail.com with the subject line “Sales Associate #987654f.” If that is the case, do exactly what it says. Not doing so will decrease your chances of getting the job and even of someone reading the email. Companies use these tests to filter out people who can’t follow directions.

Avoid SPAM words

SPAM words are words that trigger SPAM filters and can get your email send the junk mail folder. There are a few hundred of them and you can find a good list here, at Hubspot.

Be professional

One of my personal pet peeves in professional emails is “Hey, Elizabeth” or, worse, “Hey, Elizabeth!” It’s too casual and presumptuous, and exclamation marks are lazy. Is this weird? Maybe! But you never know what someone is going to hate, so you’re better off erring on the side of formality because people are rarely offended by someone being too respectful.

Insert as much relevant information as possible

This is key. Avoid generic subject lines that don’t tell the recipient anything useful. I’m not going to open an email from someone I don’t know that says “Following up” or “A question.”

And don’t waste space. Mention the purpose of your message in the subject line. If you’re applying for or asking about a job, say what job it is. If you’re applying for a data scientist position: “Data Scientist – Belinda Carmichael.” Or, if there’s a job number (or competition number), “Data Engineer #2176351– Belinda Carmichael.”

If you are following up on meeting at a networking event, say something like “Following up on Saturday’s chat” or “Continuing our conversation from Code2025.”

If you were referred by someone at the company, you can say something like “Referred by Catherine Nguyen.” This is especially good if Catherine is the CEO or holds some equally senior role.

Do get as much in there as you can in as few words as possible.

A few more tips: your email address should be professional. If it’s prettywoman1979@xemail.com or fastdriver@thisemail.com, change it to some variation on your first and last name, initials, or whatever is available. There’s no excuse for novelty email addresses in 2021.

Also, you shouldn’t have to waste subject line space on your name. It should already be there. Make sure your full name shows up as the name that appears in the “from” column, so people know who’s writing to them.

How long should the email be?

Finally, a note on length. How long should your subject line be? The definitive answer is: nobody really knows.

Some research has found that you should keep it to around 40 characters for an optimal open rate and there are even people who say that 16 characters is the best length. But the reality is that there may be no optimal length and no statistical link between subject line length and open rate.

There’s an idea that you want to avoid getting the subject line cut off, so keeping it shorter is smarter, as the number of characters displayed by devices and email providers varies from around 25-60 characters. This makes sense, but if you craft a good line, someone might open the email to see the rest of it. Like, “Hi Jenn. When we met the other day I forgot to tell you about my research in [insert relevant topic here]” which, cut off at any point, might entice the reader to open and read on.

And some research has found that longer subject lines perform better than shorter ones. One analysis of more than one billion emails found that subject lines of 90 characters and more produced the highest response rates and 30 characters or less also performed well. Thirty to 90 characters, however, was found to be a “dead zone,” with the lowest rate of opens and clicks in an email.

In other words, use as many words as you need, no more, no less.