2026-11-11
Why do we say OOF instead of OOO? Let’s rewind to the 1980s. Back then, Microsoft Xenix was the leading Unix OS. Yes, really. Microsoft ran its internal email system on Xenix, where "OOF" meant "Out of Facility": a status indicating that someone was unavailable.
The terminology later changed from "Out of Facility" to "Out of Office", but the established abbreviation survived. That is why we still say OOF today, even though OOO would appear more logical.
🔗How "Out of Office" is used today
Today, OOF can refer to both an absent person and the automatic reply they leave behind. Someone might say, "I’ll be OOF tomorrow", or ask a colleague to "set an OOF" before going on leave.
An out-of-office message is often the first response a sender receives when contacting someone who is unavailable. A good message should immediately answer the questions that matter:
- When will you return?
- Will you read or respond to email while you are away?
- Who should be contacted if the matter cannot wait?
- Has the message been forwarded, or does the sender need to take action?
A clear OOF reply sets realistic expectations, prevents unnecessary follow-ups, and helps work continue during your absence.
🔗Professional out-of-office message examples
The best OOF message depends on whether you will monitor your inbox and whether someone else can help while you are away. Choose the example that matches your actual availability.
🔗Simple and clear
Thank you for your email. I am out of the office and will return on [date]. I will respond as soon as I can after my return.
🔗With an alternative contact
I am out of the office and will return on [date]. I will not be monitoring my inbox during this time.
If your request cannot wait, please contact [name] at [email address or phone number].
🔗With limited access to email
Thank you for your message. I am out of the office and will return on [date]. I will have limited access to email, so my response may be delayed.
For urgent matters, please contact [name or team] at [contact details].
🔗More personal
Thanks for your message. I’m currently away and will be back on [date]. I won’t be checking email regularly, but I’ll get back to you as soon as I can after I return.
🔗For different projects or responsibilities
Thank you for your email. I am out of the office and will return on [date].
While I am away, please contact:
- [Name] for [project or topic]
- [Name] for [project or topic]
- [Team or manager] for matters that cannot wait
Your email has [not been forwarded / been forwarded to the responsible team].
🔗Build your own OOF message
For a more flexible message, combine one sentence from each relevant section below.
Return date
- I will return on [date].
- I expect to be back on [date].
Email access
- I will not be monitoring email while I am away.
- I will have limited access to email, so responses may be delayed.
- I will check email occasionally but may not respond until I return.
Message handling
- Your message has not been forwarded.
- Your message has been forwarded to the responsible team for review.
Alternative contact
- If your request cannot wait, please contact [name or team] at [contact details].
- For [project or topic], please contact [name] at [contact details].
Only include statements that are true. In particular, do not say that messages are being monitored or forwarded unless the relevant person or team has agreed to handle them.
🔗Technical best practices for OOF messages
Exchange and Outlook support separate automatic replies for internal and external senders. Use this distinction deliberately.
An internal reply can contain operational details such as project contacts, team responsibilities, internal phone numbers, or information about how messages are being handled.
An external reply should usually be more restrained and contain only the return date and the contact details needed by customers, partners, or suppliers.
Keep the formatting simple. Short paragraphs and ordinary text links are more reliable across email clients than complex tables or elaborate layouts. Only linked images are supported; if you include one, make sure the message remains complete and understandable when that image is blocked or unavailable. See our guide to image formats for details.
Before deployment, test both replies and verify their dates, contact details, links, formatting, and intended audience.
For organizations that need to maintain OOF replies centrally, Set-OutlookSignatures with the Benefactor Circle add-on can deploy separate internal and external reply texts based on Word or HTML templates.
🔗Bonus trivia: "little r" and "big R"
OOF is not the only piece of older email terminology still in use. Long-time Microsoft employees may call Reply "little r" and Reply All "big R":
Ctrl+R: ReplyCtrl+Shift+R: Reply All
Like OOF, the terminology has survived long after the original mail systems disappeared.
🔗Set-OutlookSignatures centralizes email signatures and out-of-office replies across every Outlook platform
Consistent branding for Marketing, centralized control for IT, and zero manual effort for employees. Sovereign by design, it keeps data within systems you already trust.
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