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How Many Mailboxes Do I Need? Calculator
Enter your SDR count, daily emails per SDR, target meetings, and reply rate to get the recommended mailbox count, domain count, warmup timeline, and estimated monthly cost at coldBirds pricing.
Your Setup
5 SDRs
1100
50 emails
10200
3 %
115
20 meetings
5200
Your Recommended Setup
Mailboxes Needed
9
At 30 emails/mailbox/day
Domains Needed
3
1 domain per 3 mailboxes (1:1:1:3)
Monthly Cost
$31.5
At $3.50/mailbox on coldBirds
Warmup Period
14 days
Before reaching full send volume
Volume Breakdown
Total daily emails250 emails/day
Monthly email volume5,500 emails/month
Estimated monthly replies~165 replies
Estimated monthly meetings~50 meetings
Cost per email$0.0057
Cost per meeting$0.63
Suggested Ramp-Up Schedule
Week 1 (Day 1–7)5–10 emails/mailbox/day
Week 2 (Day 8–14)15–20 emails/mailbox/day
Week 3 (Day 15–21)25–30 emails/mailbox/day
Week 4+ (Day 22+)Full volume: 30/day
On coldBirds' Growth plan — DNS auto-configured, warmup included, and health monitoring every 6 hours.
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