Cold email daily sending limits

Two caps, and the lower one wins

Every campaign meets a mailbox cap and a campaign cap. The mailbox cap is configured on the sending account; the campaign cap is set on the sequence. If either is low, the campaign stops when it is reached, and the provider may mark the sequence complete even though most of the list was never contacted.

That is why a campaign can look paused with thousands of untouched recipients. Check both numbers before assuming a sender failure. A mailbox with a fifty-per-day cap will stop a ten-thousand-recipient campaign every single day at fifty.

• Read the mailbox daily limit from the sending account, not from the campaign view.
• Read the campaign's own daily frequency settings separately.
• Raise the cap only for mailboxes you operate; leave customer mailboxes alone.

A raised cap still needs a warm mailbox; warm-up explains the ramp that makes it safe.

Spacing decides the real ceiling

At one message per minute you have 1,440 minutes in a day, so the arithmetic ceiling is 1,440. At thirty seconds it is 2,880. No cap above that changes anything, because the interval is the bottleneck. Raising a daily cap from 1,000 to 100,000 does not make a mailbox send faster.

This is also why volume planning should start from spacing. Decide the interval that looks human, calculate the ceiling, and then decide how many mailboxes you need for the total. Two mailboxes at one minute each are worth more than one mailbox pushed to thirty seconds if the second mailbox is available.

Additional mailboxes are the honest way to add capacity; SMTP accounts provides accounts on your own domain.

What a safe ramp looks like

There is no universal number, but the shape is consistent: start well below the target, hold for a day, and raise only if the previous day produced no blocks and no complaint pattern. A ramp that doubles every few hours is not a ramp; it is a spike with extra steps.

Worked example: a new mailbox sent 40 on day one, 60 on day two, 90 on day three and 120 on day four, with one day at each level and no blocks. On day five it moved to 200 and held. The campaign took a week to reach a useful pace, and it never produced a provider warning.

• Start at a fraction of the eventual volume.
• Hold each level for at least a day of normal sending.
• Raise only after a clean day, never after a partial one.
• Drop back immediately on a block or a complaint.

Plan the campaign around the cap, not against it

If a list has 10,000 recipients and a mailbox sends 200 a day, the campaign needs fifty days on one mailbox. That is usually unacceptable, which is why campaigns are split across mailboxes and audiences. Splitting by audience also keeps the message relevant, which is better for replies than any pacing trick.

Account for the days you will not send: weekends, holidays, and any period when replies need attention. A limit that fits the calendar is more useful than one that only fits the arithmetic.

• Divide recipients by days available, not by days in the plan.
• One campaign per mailbox; do not stack two audiences on one sender.
• Keep headroom for follow-ups, which also consume the same cap.

If you send for several clients, the pacing rules multiply; running several client campaigns covers the parallel structure.

When a low cap is the right choice

A low daily cap is not always a fault. If a campaign has fifty carefully researched recipients, capping the mailbox at fifty prevents a follow-up from overshooting the audience. The same applies to a high-value offer where every reply is handled personally and volume would outrun the ability to answer.

Set the cap from the work downstream, not from the capacity upstream. A mailbox that can send two thousand a day is not useful if nobody can answer two hundred replies. The cap is how you make the sending match the staffing.

• Small, researched audiences justify low caps.
• Match the cap to the reply-handling capacity.
• Raise the cap only when the previous level is fully handled.
• Check the provider's own cap too. Some hosts limit messages per hour as well as per day, and a campaign that looks stalled at midday is often waiting for an hourly window rather than a daily one.

Spacing, arithmetic ceiling and what to plan for

Planning figures leave room for replies, retries and the provider's own limits. They are not guarantees.

Frequently asked questions