What "N mailable from M" means

When you pick an audience in the campaign builder, a line appears underneath reading something like "3,412 mailable from 3,890".

• The second number is how many contacts the audience holds.
• The first number is how many of them can actually be emailed.
• The first number is what gets sent.

Why the two differ

Four filters sit between "in the audience" and "receives the email":

1. Suppressed — bounced, complained, or unsubscribed.
2. Invalid — the address failed validation and cannot receive mail.
3. No marketing consent — being in a list is not the same as opting in. Consent comes from the lead form's consent setting or the customer's store preference.
4. Duplicates — when several audiences overlap, each person counts once.

A gap is normal and healthy. It is the system protecting your sending reputation.

When the line turns amber

The hint turns amber when an audience has lost more than half of itself. That is worth stopping for.

It usually means the list is old, was bought, or is a lead list being treated as a mailing list. Sending to it anyway risks bounces and complaints, and those are what get campaigns paused automatically — see Why is my campaign paused?.

What to do about a large gap

• Ad-lead lists: expected. Consent comes from the form, not from membership.
• A freshly imported list losing most of itself: the source is the problem. Do not send to it at scale.
• An old list you have not mailed in a year: send to your most recent contacts first and build back up, rather than mailing everyone at once.

Next: select your audience in the campaign builder and read the mailable line before clicking Continue.