Email Subject Lines: Rules and 60 Examples by Situation
A good subject line says what the email is about and what you need, in the first few words. Be specific, put the key detail first, keep it short enough for a phone preview, and add a date or reference number when it helps. Below are the rules, weak and strong pairs, and 60 examples for common work and study situations.
The short answer
A strong subject line tells the reader what the email is and what to do, using the most important words first. "Invoice 2041 overdue: payment needed by 20 Nov" works. "Quick question" does not. Keep it short, because many mail apps cut off long subjects on a phone, and avoid anything that looks like spam.
Five rules that cover most cases
- Be specific. Name the topic, project, document or event. "Q4 budget: two figures to confirm" beats "Budget".
- Put the key detail first. Inboxes and phone screens show only the start. Lead with the topic or action, then the extra detail.
- Keep it short. There is no single length that applies everywhere, because each mail app displays a different amount. As a habit, put everything essential in the first five or six words and treat the rest as a bonus.
- State the action or deadline when there is one. "Please approve by Friday 14 Nov" saves the reader a guess.
- Write it as a plain description. Capital letters, several exclamation marks and promises such as "You won't believe this" look like spam and damage trust.
Weak and strong versions side by side
| Weak | Strong | What changed |
|---|---|---|
| Hello | Question about the 12 Nov delivery to Unit 4 | Names the topic and the date |
| Following up | Following up: marketing assistant interview on 5 Nov | Says what is being followed up |
| Urgent!!! | Contract signature needed by 5 pm Thursday | Replaces alarm with a reason and a time |
| Meeting | Meeting moved to Tuesday 18 Nov, 10:00, Room 3 | Gives the new details in the subject |
| Request | Request: extension for Essay 2 (ENG201) | Names the request and the course |
| Application | Application: Data Analyst, ref. DA-2026-17, Priya Nair | Role, reference and name in one line |
| Update | Project Falcon: week 6 status update | Names the project and the period |
| Re: Re: Re: Fwd: stuff | Revised floor plan for the Leeds office (v3) | A clean, new subject describes the real content |
60 email subject line examples
Each line is a template, not a promise that it will be opened; context and relationship matter more than wording.
Job applications (1-10)
- Application: Marketing Assistant, ref. MA-2026-08, Tom Hughes
- Junior Developer role: application from Aisha Khan
- Application for Customer Service Advisor (advert on [site], 3 Nov)
- Internship application, Summer 2027: Finance, Elena Rossi
- Following up on my application for Project Coordinator
- Thank you for the interview on Tuesday 4 Nov
- Documents you requested: references for Sam Lee
- Availability for interview, week of 17 Nov
- Accepting the offer: Operations Analyst, start date 5 Jan
- Withdrawing my application for Sales Executive
Requests and questions (11-20)
- Request: 15 minutes to discuss the Leeds proposal
- Could you review the attached budget by Thursday?
- Question about invoice 2041 (amount differs from quote)
- Request for a reference letter, deadline 28 Nov
- Extension request: Essay 2, ENG201, due 14 Nov
- Access request: shared drive "Finance 2026"
- Request for a quote: 40 office chairs, delivery by 15 Dec
- Could you confirm the venue for the 21 Nov workshop?
- Permission to use your chart in our report
- Question about the group project marking criteria
Follow-ups and reminders (21-30)
- Reminder: timesheet due Friday 14 Nov
- Following up: quote sent on 3 Nov
- Gentle reminder: invoice 2041, due 20 Nov
- Checking in on the Falcon proposal
- Did the revised contract reach you?
- Still need: signed consent forms (7 of 24 received)
- Action items from Monday's planning meeting
- Second reminder: survey closes Friday
- Any update on my refund request, ref. RF-77120?
- Last call: sign-ups close Wednesday 12 Nov
Meeting changes and scheduling (31-40)
- Meeting moved to Tuesday 18 Nov, 10:00
- Cancelled: team stand-up on Thursday 13 Nov
- Can we reschedule our call from Monday to Wednesday?
- Agenda for Thursday's budget review
- Please confirm attendance: board meeting, 25 Nov
- New room for tomorrow's workshop: Room 3B
- Minutes from the 5 Nov project meeting
- Which time suits you: 9:30 or 14:00 on Friday?
- Invitation: client lunch, Friday 21 Nov
- Running 15 minutes late to the 11:00 call
Introductions and networking (41-47)
- Introduction: Mei Tanaka (design) and Carlos Ruiz (product)
- Recommended by Dana Lee: question about your research
- Following up after the Manchester Data Meetup
- Interested in your talk on supply chains
- Thank you for your advice on 6 Nov
- Collaboration idea: student newsletter and your society
- Request to connect: speaking at the spring conference
Customer, supplier and admin messages (48-54)
- Your order 48213 has shipped
- Problem with order 48213: cracked screen on delivery
- Updated opening hours from 1 December
- Payment received for invoice 2041: thank you
- Complaint: delayed delivery of order 48213
- Policy update: remote working from 1 Jan 2027
- Out of stock: alternative for item 8832?
Newsletters and announcements (55-60)
- November news: new library hours and exam timetable
- What's new at Northgate Community Centre this month
- Three ways to save on your energy bill this winter
- Join us: open evening on Thursday 20 Nov, 6 pm
- Welcome to the team: Priya Shah, Finance
- Survey results and what we will change next term
Subject lines for replies that change topic
When a thread drifts to a new subject, change the subject line so the email can be found later. Keep the old context in brackets:
- Original: "Re: Project Falcon: week 6 status"
- Better: "Falcon: new budget question (was: week 6 status)"
If you only want to forward an old email, edit the subject so that it says why: "Fwd: Supplier contract, for your review before Friday". For help writing the body of a follow-up, see how to write a follow-up email.
Reference numbers and dates
Reference numbers help the right person find your message. Put them after the topic, so that the first words are still readable:
- "Refund request, ref. RF-77120"
- "Application: Data Analyst, ref. DA-2026-17"
- "Invoice 2041: payment due 20 Nov"
Dates: pick one format and make it unambiguous. In writing for an international audience, spell out the month ("14 Nov" or "Nov 14"), because "03/11" means 3 November in the UK and 11 March in the US. Add the weekday when the date is near ("Fri 14 Nov"), as a quick check for typing errors.
Capitalisation: title case vs sentence case
Both are used in professional email, and neither is wrong. Sentence case ("Meeting moved to Tuesday 18 Nov") looks conversational and is easier to read. Title Case ("Meeting Moved to Tuesday 18 Nov") looks more formal and is common in newsletters and announcements. Choose one style for each type of message and keep it consistent. Avoid ALL CAPS, which reads as shouting.
For proper nouns and product names, keep their normal capitalisation either way. If you write a subject line with a colon, a capital after the colon is optional in sentence case; just be consistent.
Mistakes to avoid
| Mistake | Why it hurts | Fix |
|---|---|---|
| Empty subject | Looks careless and can be filtered | Always write one |
| "Hi" or "Question" | Says nothing | Name the topic |
| Putting the whole message in the subject | Gets cut off | Keep the detail for the body |
| All caps or "!!!" | Looks like spam | Use plain words and a clear deadline |
| "Urgent" for routine mail | Teaches people to ignore it | Use it only when something is truly time-critical |
| Old subject on a new topic | Hard to search | Change it |
| Clickbait for a work email | Damages trust | Describe the real content |
| Different spelling or typos | Looks careless | Proofread the subject as well |
Using AdeptWrite for subject lines
Subject lines are short, so typos stand out. Run your draft through the Spell Checker (choose American or British English) and the Grammar Checker. If a subject line sounds too blunt for a manager or too stiff for a colleague, the Tone Changer can offer another version. The Email & Letter Writer can draft a whole email from your notes; the result is generated text, so check every date, name and number yourself. Each run is limited to 6,000 characters.
Related guides: how to write a professional email, professional email examples and email etiquette.
A quick checklist before you press send
- Does the subject say what the email is about?
- Are the most important words at the start?
- Is there a deadline, date or reference number that the reader needs?
- Would it still make sense in a search a month later?
- Is it free of ALL CAPS, spam words and extra exclamation marks?
- Have I changed the subject if the topic has changed?
Try the tools
Frequently asked questions
How long should an email subject line be?
There is no fixed limit, because mail apps show different amounts. Put the key information in the first five or six words, then add detail if it helps. Subjects that are shorter than a full sentence usually display fully on both computers and phones.
What makes a good email subject line?
A good subject line is specific, puts the main topic first, and states any action or deadline. "Contract signature needed by 5 pm Thursday" tells the reader more than "Urgent". Add a reference number or date when it helps them find or act on the email.
Should I change the subject line when the topic changes?
Yes. Start a new message or edit the subject so it describes the new topic, and keep the old context in brackets if it helps, for example "Falcon: new budget question (was: week 6 status)". This makes the email easier to find and answer later.
Should email subject lines use title case or sentence case?
Either is acceptable. Sentence case reads as more conversational, and title case looks more formal, especially for newsletters. Choose one style and use it consistently. Avoid writing the whole subject in capital letters, because it looks like shouting.
Related guides
- How to Write a Professional Email: Structure, Tone Ladder and Six Templates — A professional email has six parts: a specific subject line, a greeting, the purpose in the first sentence, only the det…
- 15 Professional Email Examples You Can Copy and Customise — These fifteen professional email examples cover the situations people search for most: asking for a meeting, chasing an …
- How to End an Email: 40+ Sign-Offs, Closing Lines and When to Use Them — End an email with a closing line that states the next step, then a sign-off and your name. "Best regards" and "Kind rega…
- CC vs BCC in Email: What They Mean and When to Use Each — To is for the people who must act, CC (carbon copy) is for people who should be kept informed, and BCC (blind carbon cop…