Setting up the right number of email accounts and domains is critical for cold email deliverability. This guide helps you calculate your ideal setup based on your outreach volume.
Before we get into the math, here are the key limits to keep in mind:
Inboxes per domain - 2 max
Emails per day per warmed-up mailbox - 30 max (safe), 20/day (safer, recommended)
Warm-up period - 2–4 weeks before full volume
Why 2 inboxes per domain? More than 2 mailboxes on the same domain increases the risk of the entire domain getting flagged. If one inbox gets marked as spam, it can drag down all others on the same domain.
Why 20–30 emails per day? Email providers like Google and Microsoft monitor sending patterns. Staying under 30/day per mailbox keeps you well within safe limits. 20/day is the conservative, safer choice - especially for new domains.
Formula: Daily outreach target / emails per mailbox per day = mailboxes needed. Then: mailboxes needed / 2 = domains needed.
Riskier (30/day): 4 mailboxes, 2 domains
Safer (20/day): 5 mailboxes, 3 domains
Riskier (30/day): 10 mailboxes, 5 domains
Safer (20/day): 15 mailboxes, 8 domains
Riskier (30/day): 34 mailboxes, 17 domains
Safer (20/day): 50 mailboxes, 25 domains
Not sure about daily volume? Think about your total lead list and how fast you want to reach everyone (based on 20 emails/day per mailbox):
Lead list size | 30 days | 60 days | 90 days |
|---|---|---|---|
1,000 leads | 2 domains, 4 mailboxes | 1 domain, 2 mailboxes | 1 domain, 2 mailboxes |
5,000 leads | 9 domains, 17 mailboxes | 5 domains, 9 mailboxes | 3 domains, 6 mailboxes |
10,000 leads | 17 domains, 34 mailboxes | 9 domains, 17 mailboxes | 6 domains, 12 mailboxes |
25,000 leads | 42 domains, 84 mailboxes | 21 domains, 42 mailboxes | 14 domains, 28 mailboxes |
Actual numbers may vary based on reply rates and follow-up sequences.
Purchase dedicated domains for your outreach. Use variations of your brand name:
yourcompany-mail.com
yourcompany.io
getyourcompany.com
tryyourcompany.com
You can purchase domains and mailboxes directly from Email Accounts - click the Add Account button to see our partner offers.
Important: Never use your primary company domain for cold outreach. Always use separate, dedicated domains.
Set up 2 mailboxes per domain. For example:
You can purchase pre-configured Gmail and Outlook mailboxes at $3.50 each from our partners - go to Email Accounts, click Add Account, and check the "Getting Started" section for partner links and exclusive discounts.
Add your accounts in Email Accounts and configure DNS records (SPF, DKIM, DMARC).
Enable warmup for all accounts. MailBeast will automatically ramp up sending volume over 2–4 weeks to build sender reputation.
Once warmup is complete, start sending campaigns. MailBeast will automatically distribute your outreach across all connected accounts to maximize deliverability.
Rotate domains - Don't send from the same domain every day. Let MailBeast distribute across your accounts.
Start conservative - Begin with 20 emails/day per mailbox. You can increase to 30 after a few weeks of consistent sending with good engagement.
Monitor health scores - Keep an eye on your account health scores in MailBeast. If a score drops, reduce volume on that account.
Plan for growth - If you plan to scale, buy domains and start warming them up early. It takes 2–4 weeks before a new domain is ready for full volume.
Follow-up sequences count - Remember that follow-ups also consume your daily quota. If you have a 3-step sequence, one lead uses 3 sends across the sequence lifetime.
