A good business email subject line names the topic and the action in a few plain words, so the reader knows what you need before opening it. Put the key words first, include a name, date or number when it helps, and never suggest something the email does not contain.
| Situation | Pattern | Example |
|---|---|---|
| Follow-up | Topic + where it stands | Quote for kitchen refit: any questions? |
| Request | Action + topic + deadline | Approval needed: spring menu by Friday |
| Introduction | Who + why it matters to them | Intro: Dana Cho, wedding florist in your area |
| Invoice | Invoice number + amount or date | Invoice 1042 from Oak Lane Studio, due 30 Nov |
| Meeting request | Meeting + topic + option | 20 minutes Tuesday to plan the store launch? |
Updated
Most work email gets sorted by subject alone: open now, later or never. A clear subject line is less about being clever and more about saving the reader a step. Below are patterns for the emails small businesses send most, around sixty of our own examples you can filter, and a counter to check yours as you write.
Your email app writes the subject as a header line. Non-English letters and emoji are turned into an encoded-word; a long subject is folded with a line break and a leading space. Readers only ever see the plain text.
The second line spells Café menu for March in Base64 inside an RFC 2047 encoded-word. The third shows a long subject folded onto two lines.
Subject: Invoice 1042 from Oak Lane Studio, due 30 Nov
Subject: =?UTF-8?B?Q2Fmw6kgbWVudSBmb3IgTWFyY2g=?=
Subject: Agenda for Monday's planning meeting, plus the updated
budget sheet and the venue options we discussedDraft the email first, then ask what one thing the reader should do. That action, plus the topic, usually makes the best subject line. If you cannot name one action, the email may be trying to do too much.
Swap vague words for specific ones. Quick question becomes Question about your delivery days. Update becomes Your order ships Thursday. The specific version is the same length and gets the job done before the email is even opened.
The email standard describes the subject as a short string identifying the topic of the message. Every header line must stay under 998 characters and should stay under 78; longer subjects are folded onto continuation lines by the sending software, which readers never see.
Any limit on how much an inbox displays is set by each email app and screen size, not by a standard. That is why this page gives no single magic number and instead suggests front-loading the words that matter.
There is no official ideal length, and each email app shows a different amount. Short enough that the key words show first is the safe rule. The email standard RFC 5322 says a header line should be no more than 78 characters, and longer subjects are simply folded onto extra lines.
Not if it is true and rare. A clear deadline usually works better, for example Reply needed by 3pm: delivery address, because it says why and when instead of only raising the alarm.
For commercial email in the US, yes. The FTC's CAN-SPAM guide says the subject line must accurately reflect the content of the message, and that the law makes no exception for business-to-business email. This is not legal advice.
Yes. Email software encodes them into a format called an encoded-word, defined in RFC 2047, so they arrive intact. Use them sparingly in work email, as not every reader welcomes them.
Name the original topic so the reader recognises it, then say what you need now: Following up: website quote from 3 October, or Still interested in the Saturday slot?
Related: Email subject line tester, How to get a free business email, Abandoned cart text messages.
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