What is Warm Inboxes?

Warm Inboxes is your trusted platform for purchasing prewarmed and regular email accounts for Google Workspace and Microsoft 365. Accounts are ready for successful email outreach with high deliverability and ease of setup.

What are prewarmed email inboxes?

Prewarmed email inboxes are email accounts that have been gradually conditioned over time to send emails at scale without triggering spam filters. They are ready to use immediately with warm deliverability.

Do prewarmed inboxes include domains?

Yes, free prewarmed .com domains are included on every package, saving you $12+ per domain.

How much do prewarmed inboxes cost?

Prewarmed inbox packages start at $18/month for 3 inboxes with a free prewarmed .COM/.CO domain on quarterly billing ($24 month-to-month). Google Workspace fresh inboxes start at $2.00/inbox/month at volume.

Which email providers do you support?

We provide email accounts on Google Workspace and Microsoft 365/Azure.

Can I use my own domains?

Absolutely. If you already own a domain, we can help you set it up with mailboxes and ensure everything is configured correctly for optimal performance.

What is your refund policy?

We do not offer refunds. We encourage you to review our terms carefully or reach out with any questions before making a purchase.

Home › Blog › How Many Cold Email Domains Do I Need for 300 Emails per Day?

Infrastructure · 9 min read

How Many Cold Email Domains Do I Need for 300 Emails per Day?

The full formula with worked examples for 100, 300, 500 and 1,000 sends/day, plus the rotation buffer most calculators forget.

Published Jul 19, 2026 by Huzayfa Majeed, WarmInboxes

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Prewarmed & Fresh Inboxes

Google, Microsoft 365 and Azure inboxes with free prewarmed domains and DNS configured before you log in. Prewarmed inboxes send the same day you order.

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