You have written the newsletter. It has a good tip, a real offer and a photo of the new stock. Now there is one empty box left at the top, and whatever you type into it decides whether anyone reads the rest. So you stare at it, type “October Newsletter”, delete it, and try something with three exclamation marks.
Good email subject lines are less about cleverness than most advice suggests. For a small business writing to people who chose to hear from it, the subject line that works is usually the one that says plainly what is inside. This guide covers how to write subject lines that way, how to use the preview text beneath them, the patterns that look like spam, and how to test without fooling yourself.
What the inbox shows before anyone opens
On a phone, a reader decides in a moment, based on three things shown together:
- The sender name. Do they recognise you? This matters more than the subject. Use the same name every time, the one customers know you by.
- The subject line. What is this email about?
- The preview text. A grey line under the subject that adds detail, or, if you leave it empty, shows whatever text the email happens to start with.
Write all three together, as one short message. A good subject next to “View this email in your browser” as the preview wastes half the space.
How much of each shows depends on the phone, the mail app and the screen size, so put the important words first in both.
Say what is inside
The most reliable subject line is a plain description of the most useful thing in the email. Readers who signed up to hear from you want to know whether this one is worth their time now.
- Name the specific thing: the product, the date, the change, the tip.
- Lead with the part that affects the reader: “Clinic closed on Friday” before “An update from the team”.
- If there is a real deadline, say it plainly.
- Match the subject to the content. If the subject promises a recipe, the recipe should be near the top.
Plain does not mean dull. “Three plants that survive a north-facing balcony” is plain and still interesting, because it is specific.
One email, one main subject. If you are tempted to write “News, offers, events and tips”, the email is probably trying to do too much. Pick the strongest item for the subject line and mention the rest inside.
Subject lines rewritten: before and after
| Before | After | Why it is better |
|---|---|---|
| October Newsletter | New winter batch timings, and a free trial class on Saturday | Tells the reader what changed and what is on offer |
| You won’t believe this!! | Our festive gift boxes are ready to pre-order | States the news instead of hiding it |
| Important update | We have moved: new address from Monday | Specific, and clearly worth opening |
| Don’t miss out | Last day for the monsoon servicing offer is Sunday | A real deadline instead of vague pressure |
| Hi there | How to tell if your water filter needs changing | Promises a useful answer |
| SALE SALE SALE | Summer cotton range: selected styles reduced this week | Calm, specific, less likely to look like spam |
Email subject lines that look like spam
Spam filters look at the whole message and at how recipients react, so a single word rarely sinks an email. Still, some subject line habits both annoy readers and resemble junk.
- Capital letters for whole words or the whole line. It reads as shouting.
- Strings of exclamation marks or symbols.
- Fake replies and forwards. Adding “Re:” or “Fwd:” to a newsletter is deceptive. In the US, the law on commercial email expects subject lines not to mislead about the content, and other places take a similar view.
- Fake urgency. “Final hours!” on an offer that runs again next month teaches people to ignore you.
- Bait. “Your account” or “Your order” on a promotion, or anything that pretends to be a transaction.
- Clickbait. “You won’t believe” and “This changes everything” bring opens and then disappointment, and disappointed readers unsubscribe.
If your mail is landing in junk, subject lines are seldom the main reason. Our guide to newsletters landing in spam covers the causes that matter more.
Preview text: the second line
Most email platforms have a field for preview text, sometimes called preheader text. Use it every time.
- Add detail the subject could not fit: “Saturday 10am, ages 8 to 12, bring water and a towel.”
- Do not repeat the subject word for word.
- Do not leave it blank, or the app will show the first text it finds, which may be “Having trouble viewing this email?” or your logo’s alt text.
- Keep the most important words at the start, as with the subject.
Personalisation that helps, and that does not
Putting a first name in the subject line is the best-known trick and among the least reliable. It can help when the email is genuinely personal, such as a service reminder for that customer’s car. On a general newsletter it can feel like a mail merge.
It goes wrong when the data is messy. “Hi PRIYA SHARMA”, “Hi priya.s88” or “Hi ,” in front of a thousand people looks careless. If you use names, check the field first and set a fallback such as no name at all.
Better personalisation is relevance: sending the email about school uniforms to parents who signed up for school news, and the one about office furniture to business buyers. That is a segmentation question rather than a subject line one.
Emojis, length and other small choices
- Emojis: one that fits the topic can add a little colour. Several in a row look like junk, and some display as empty boxes on older devices.
- Length: there is no ideal count. Short is easier to read on a phone, but a slightly longer, specific line beats a short vague one.
- Questions: fine when they are real questions the reader has, such as “Is your AC ready for summer?”.
- Brand name in the subject: usually unnecessary if the sender name already shows it.
Testing subject lines with a small list
Many platforms offer A/B tests: two subject lines go to small samples, and the winner goes to everyone else. On a small list, treat the results with caution.
- With few recipients, the difference between two versions may just be chance.
- Open counts are unreliable because some mail apps register opens automatically, so a test judged on opens can pick the wrong winner. Our explanation of why open rates mislead covers this.
- Judge by clicks where your platform allows it, and look at patterns over several sends rather than one test.
A simpler method suits most small businesses: keep a short note of each subject line, the clicks and the replies it brought, and look back every few months. You will see which kinds of subject your own readers respond to.
What happens after the open matters as much. A clear layout that reads well on a phone, covered in our guide to designing emails for small screens, keeps people reading. The full set of steps for a newsletter programme is in our email marketing walkthrough, and our digital marketing guide puts the newsletter in context beside the social posts and ads that may be announcing the same news.
Frequently asked questions
Is it fine to use the same subject line format every month?
A consistent format can help regular readers recognise your newsletter, as long as each subject still says what is inside that month. “Green Leaf monthly: balcony herbs and new pots” works. A bare “Monthly newsletter, issue 14” every time tells people nothing and gives them no reason to open.
Should I write the subject line before or after the email?
After, in most cases. Once the email is written, you know which item is strongest and can describe it accurately. Writing the subject first tends to produce a promise the email then has to stretch to fit. Write two or three options and pick the clearest.
Can a subject line make an email legally misleading?
It can. In the US, the law on commercial email expects subject lines not to mislead recipients about the content, and consumer protection rules elsewhere take a dim view of deceptive marketing too. This is general information, not legal advice. Writing a subject that honestly describes the email keeps you clear.
Do subject lines matter as much for automated emails?
Yes, and they are easier to get right because you have time to think them over. A welcome, a reminder or a review request is read by every new person who triggers it, so a clear subject is worth more there than on a one-off newsletter. Review them along with the email text.
If you would like help writing subject lines and newsletters that sound like you, our email marketing services cover drafting and editing as well as sending.
Next in this series: Email Open Rate Explained: Why It Misleads You
