Three limits decide how much you can send: the daily limit on each mailbox, the pace you set on the campaign, and the monthly email allowance of your plan. All three are hard stops. Nothing is sent past a limit, and nothing is billed as overage.
The daily limit on each mailbox
Every mailbox has a Daily sending limit, set when you add the mailbox and editable in its settings. To change many mailboxes at once, select them and use the bulk settings, which accept 1 to 500 Emails per day.
The limit belongs to the mailbox, not to a campaign. If one mailbox sends for three campaigns, all three draw on the same daily number. When a mailbox reaches its limit, it sends nothing more that day.
Keep the number modest. A limit that looks low per mailbox is the point: volume comes from adding mailboxes, not from pushing one harder.
How a campaign spreads sends across mailboxes
In the campaign's Options, the Sending tab has Accounts to use, where you select one or more mailboxes to send from.
With several mailboxes selected, each email goes to the active mailbox that has sent the least so far, which keeps the load even. Two things take a mailbox out of that rotation:
- It is still warming up. A mailbox in warmup is never used for campaign email. The campaign shows Waiting on warmup until at least one selected mailbox is active. See What is domain warmup and how long does it take?
- Its reputation has dropped. A mailbox rated bad gets a smaller share of sends, and one rated very bad is paused. See Mailbox health and reputation.
The pace of a campaign
Also on the Sending tab, Sending Pattern controls the spacing between sends and how many new leads start each day:
- Minimum time is the shortest gap between two sends, in minutes.
- Random additional time adds a random number of minutes on top, so sends do not land on a fixed beat.
- Max new leads caps how many new leads the campaign starts per day.
The Schedule tab sets the days and hours the campaign may send. Outside that window nothing goes out, whatever the limits allow.
The monthly allowance of your plan
Each plan includes a number of emails per month across the whole workspace.
| Plan | Emails per month | Mailboxes |
|---|---|---|
| Trial | 50 | 1 |
| Starter | 10,000 | 10 |
| Professional | 100,000 | 50 |
| Enterprise | 500,000 | 250 |
When the allowance is used up, campaign sending stops until the allowance resets or you move to a larger plan. See Plans and the free trial. To estimate how many mailboxes and which plan a target volume needs, use the free outreach budget calculator.
Which limit is holding a campaign back
Work from the smallest number outwards: the schedule window, then the mailbox limits, then Max new leads, then the monthly allowance. Why is my campaign not sending? goes through each check in order.