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Cold Email Mailbox Calculator
Find out exactly how many mailboxes and domains you need for your cold email volume — and see how much you'll save with ColdRelay vs Google Workspace or Outlook.
1,000
100/day20,000/day
Mailboxes Needed
250
at 4 emails/mailbox/day (2 outbound + 2 warmup)
Free Domains Included
2
$30/yr saved · 1 per 100 mailboxes
Monthly Cost Comparison
Best Value
ColdRelay
$213
$0.85/mailbox · Growth (200–999)
Google Workspace
$1,800
$7.20/user/month
Microsoft 365
$1,500
$6.00/user/month
You Save vs Google
$1,588/mo
You Save vs Outlook
$1,288/mo
Annual Savings vs Google
$19,050/yr
ColdRelay Pricing Tiers
Starter (1–199)
$1.00
/mailbox/mo
Growth (200–999)
$0.85
/mailbox/mo
Scale (1,000–4,999)
$0.70
/mailbox/mo
Agency (5,000+)
$0.55
/mailbox/mo
FAQ
Frequently Asked Questions
Related guides
Going deeper on cold email volume
The calculator gives you the headcount. These guides explain how to keep those mailboxes healthy once they're sending — and why deliverability beats raw volume.
Guide
Cold Email Bounce Rate Explained
Bounce rates above 3% wreck deliverability fast. How to measure them, why mailboxes burn, and what to do about it.
Guide
What's a Good Open Rate for Cold Email?
Benchmarks by industry, list quality, and warmup state. Plus why open-rate tracking lies and what to trust instead.
Guide
Email Warmup Tools: Honest Comparison
What warmup actually does, why most tools overpromise, and how ColdRelay's built-in warmup compares to standalone tools.
Pillar
Cold Email Deliverability: The Complete Guide
Mailbox count is one input — reputation, warmup, authentication, and list hygiene all stack. The full picture.
Ready to Scale Your Cold Email?
ColdRelay sets up your mailboxes, domains, DNS, and warmup automatically. Pay a fraction of what Google or Outlook charges — with better deliverability built in.
Get Started Free →