Cc vs Bcc: what each email field does

Cc vs Bcc: the short answer

Put someone in To if the message is addressed to them and you expect them to act or reply. Use Cc when they should see the exchange but don't need to do anything. Use Bcc when they should receive a copy without the other recipients seeing their email address. For example, put a project owner in Cc for visibility, or put an outside recipient in Bcc when you need to keep their address hidden from the group.

In Gmail, Bcc recipients can’t see who else was Bcc’d, and people in To and Cc won’t know anyone was added to Bcc. Other services may handle Bcc differently, so don’t treat it as a universal privacy guarantee. Remove anyone who doesn’t need the message from the thread, a practice covered in the email etiquette guide on who belongs in a thread.

What To, Cc, and Bcc technically mean

To, Cc, and Bcc are message header fields. To and Cc addresses normally remain visible in the delivered message, while Bcc addresses are meant not to be revealed to the other recipients.

Bcc isn’t handled identically by every sending system. A system may remove the Bcc field, send separate copies to blind recipients, or send a copy that retains the full Bcc list. In that last case, Bcc recipients can see one another. Gmail hides Bcc addresses from To and Cc recipients and from other Bcc recipients, but that guarantee applies to Gmail rather than every service. For sensitive messages, verify how your service handles Bcc or send separate messages.

Several people can share the To field when the message is directed to all of them. To doesn’t assign responsibility, so put the responsible person directly in the request. If an account lead writes to four client contacts and the finance lead must approve the schedule, put all four contacts in To and write, “Priya, please approve the schedule by Thursday.”

What Reply and Reply All do

Reply goes to the original sender only in classic Outlook and Microsoft 365. Reply All goes to the sender plus recipients on the To and Cc lines. Microsoft also advises considering whether everyone needs the reply.

A blind recipient doesn't appear on the To and Cc lines. If people reply all to a message, people in Bcc won't see the reply. RFC 5322 warns that a hidden reader who chooses Reply All reveals to everyone on the To and Cc lines that they were quietly copied.

Before answering a group thread, decide who needs the information.

When to use To, Cc, or Bcc

Bcc and privacy

If you're sending one routine message to people who don't know each other, Bcc is the minimum privacy protection. Addresses in To or Cc are visible to the group, and the list can reveal both who you're contacting and why those people are receiving the same message. Put your own address in To and add everyone else in Bcc.

In March 2023, the UK Information Commissioner's Office formally reprimanded NHS Highland over an email to 37 people likely to be accessing HIV services that exposed the recipients' addresses through Cc, with one person confirming they recognised four other individuals. Before sending, expand the Bcc field and check that none of the recipients appears in To or Cc.

Bcc may be enough when only the address list needs to stay private. If being part of the group is itself sensitive, don't rely on a single group message. Send a separate message to each person or use a mailing tool that generates an individual copy for every recipient. In Gmail, create a contact label and send to it with Bcc, then verify the recipient fields before you click Send.

Should you secretly Bcc someone?

You quietly Bcc your manager on a tense thread. If the manager hits Reply All, everyone on the To and Cc lines learns the manager was reading.

Use an explicit Cc when the other person belongs in the conversation. A line such as "I'm copying Maya because she owns the contract terms and can answer the second question" tells everyone who is present and why.

Bcc after an email introduction

After connecting two people, an introducer may write, "Thanks both. I'll move myself to Bcc so you can coordinate directly." That line tells the visible recipients why later Reply All messages won't include the introducer.

If you're still writing the introduction itself, write what each person gets out of meeting the other, and consider starting from the examples in the introduction email guide.