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Mailbox Requirements Calculator
Calculate exactly how many mailboxes you need for your cold email campaigns and find the most cost-effective plan.
Campaign Parameters
5,00020,00035,00050,000
7 days35 days62 days90 days
5132230
0.5%3.7%6.8%10%
Recommended Settings:
- • 10 emails/day is the safe daily limit
- • 15 emails/day is the optimal balance
- • 20-25 emails/day is the maximum (risky)
- • Above 25 emails/day is very risky
- • 14-day minimum warmup period for new mailboxes
- • 2-3% reply rate is typical for cold email
Your Requirements
45
Mailboxes Required
To send 20,000 emails in 30 days
Daily Volume
667
emails/day total
Expected Replies
500
17/day average
Recommended Plan
Best Value
Agency
30 mailboxes included + 15 add-on mailboxes
$121.5
per month
Base Plan: $81/mo
+ 15 add-ons × $2.7 = $40.50
$0.24
Cost per Reply
$2.70
Per Mailbox/Month
Mailbox Management Best Practices
Warmup Period
We recommend warming up new mailboxes for 14-30 days before starting campaigns
Gradual Scaling
Start with 5-10 emails/day and gradually increase to maximum 15-20 emails/day
List Quality
Use verified email lists to maintain low bounce rates and protect reputation
Pro Tip:
It's better to have more mailboxes sending fewer emails each than to push the limits. This approach improves deliverability and reduces the risk of being marked as spam.