The 30-Day Email Warmup Schedule

The most common warmup mistake is treating it as a fixed calendar period — four weeks, then full volume. Warmup is a ramp governed by feedback, not a countdown. This is the schedule to start from, and the signals that tell you to hold, slow down, or proceed.

Before day one: prerequisites

None of the schedule below works if these are not true:

• Domain registered at least 4 weeks ago and resolving to a real page.

• SPF, DKIM and DMARC published and verified passing — confirmed by reading the Authentication-Results header of a test message, not by assuming. See the authentication guide.

• Custom tracking domain configured, or open tracking disabled.

• A separate domain from your primary business mail.

• Mailbox connected to your warmup tool over OAuth or SMTP/IMAP.

Starting warmup on a domain with broken DKIM does not build reputation — it accumulates evidence that you are an unauthenticated sender.

The 30-day ramp schedule

Per inbox. If you are running ten inboxes, each follows this curve independently.

DayWarmup emails/dayReal outreach/dayTotal/day 1–3303 4–7606 8–1010010 11–1414519 15–1718826 18–21221234 22–24251540 25–28282048 29–30302555 Steady state25–30 (ongoing)25–4050–70

Three principles are encoded in that curve:

1. No real outreach for the first ten days. The domain has no reputation to spend. Warmup only.

2. Total daily volume never jumps more than roughly 30% week over week. The rate of change matters as much as the absolute number.

3. Warmup does not stop when outreach begins. It continues indefinitely at 25–30 per day, because reputation decays without ongoing positive engagement.

The ceiling

Do not exceed roughly 50 real outreach emails per inbox per day, even after months of clean sending. The ceiling is not about what the provider technically permits — Google Workspace allows far more — it is about pattern. A mailbox sending 150 cold emails daily looks like a machine regardless of its history.

To send more, add inboxes. Ten inboxes at 30 emails a day is 300 emails daily at low risk. Three inboxes at 100 a day is the same volume at high risk. This is why per-inbox pricing is a deliverability problem as much as a cost problem: platforms that charge per mailbox push you toward the second configuration.

Spread inboxes across two or three separate domains, so one domain developing a problem does not stop all outreach.

Signals to hold or slow down

Check these at the end of each week and adjust before advancing:

SignalAction Inbox placement below 90%Hold current volume for a week; do not advance Warmup mail landing in spam at allReturn to warmup-only, drop to week-one volume Bounce rate above 3% on real sendsPause outreach, re-verify the list, resume at half volume Any spam complaintPause, review copy and targeting before resuming Reply rate under 1% on real sendsLikely a placement problem — seed test before continuing Authentication header shows anything but passStop immediately and fix DNS

Holding a week costs you a week. Pushing through a bad signal can cost you the domain.

Variations by situation

A domain with prior sending history

If the domain has sent legitimate business mail for months, compress the schedule to 10–14 days: start at 10 per day, reach 30 by day ten, begin outreach at day seven. The reputation base already exists.

A recovering domain

After a deliverability failure, extend to six to eight weeks and start lower — 2 per day for the first week. Confirm delisting from any blocklist first, and fix the original cause before warming. If the domain has repeated complaint spikes or a Spamhaus listing, evaluate whether replacing it is cheaper than rehabilitating it.

Adding inboxes to an established domain

A new mailbox on a domain with strong reputation warms faster than a new domain, but still needs its own ramp — reputation attaches to both the domain and the individual sending address. Use a 14-day compressed schedule.

Microsoft 365 versus Google Workspace

Microsoft tends to weight authentication and volume patterns more heavily; Google weights engagement more heavily. In practice this means Microsoft-hosted inboxes benefit from an extra week of conservative ramp, and any DKIM alignment problem shows up on Outlook first.

Sending pattern within the day

The daily total is not the only variable. How the sends are distributed matters:

• Spread across business hours in the recipient's time zone, roughly 8am to 6pm.

• Randomise intervals. Emails going out at exactly 90-second intervals is a machine signature. Vary between two and fifteen minutes.

• Weekdays only during warmup. Weekend outbound volume on a new domain is unusual.

• No bursts. Forty emails in one minute defeats the purpose of a low daily total.

Any competent warmup tool handles this automatically; verify yours does rather than assuming.

Automating the ramp

Managing this by hand across ten inboxes is impractical — it is 300 messages a day requiring genuine replies. AlienMail runs the schedule automatically on every connected mailbox, free and with no inbox limit, generating conversational reply threads, performing spam-folder rescue, and reporting placement per inbox so you can see which mailbox is ready to advance and which needs to hold.

Because warmup sends are never billed against credits, running the full 30-day ramp on twenty inboxes costs nothing. See the warm-up tool.

Frequently asked questions

How long should email warmup take?

Three to four weeks for a new domain before meaningful outreach volume, 10–14 days for a domain with existing sending history, and six to eight weeks for a recovering domain. Then it runs indefinitely underneath live campaigns.

How many emails per day during warmup?

Start at 3 per inbox per day and increase to 30 over four weeks. Steady state is 25–30 warmup emails per inbox per day, permanently.

Can I speed up warmup?

Not safely. The mechanism depends on a gradual, plausible increase in volume over time; compressing it removes the signal you are trying to create. The only legitimate accelerator is starting from a domain that already has sending history.

Should I stop warmup once campaigns are running?

No. Reputation decays without ongoing positive engagement, and live cold campaigns generate far less engagement than warmup does. Run both continuously.

What if I need to send 1,000 emails a day?

Use 25–35 inboxes across three or four domains, each warmed independently and capped at 30–40 sends per day. Do not reach that volume by raising per-inbox limits.