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Cold email mailbox
calculator

Calculate exactly how many mailboxes you need for cold email campaigns. Find the most cost-effective plan based on your volume and timeline.

CONFIGURE YOUR CAMPAIGN

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 maximum (risky)
  • • Above 25 emails/day is very risky
  • • 14-day minimum warmup for new mailboxes
  • • 2-3% reply rate is typical for cold email

CALCULATION RESULTS

Your requirements

45
Mailboxes Required
To send 20,000 emails in 30 days

667

Daily Volume

500

Expected Replies

Recommended plan

Best Value

Agency

30 mailboxes included + 15 add-on mailboxes

$121.5
per month

Pricing Breakdown:

Base Plan: $81/mo

+ 15 add-ons × $2.7 = $40.50

$0.24
Cost per Reply
$2.70
Per Mailbox/Month

Ready to launch your campaign?

Get 45 mailboxes with the Agency plan

Get Started Now

Understanding mailbox requirements

A cold email mailbox calculator determines exactly how many email addresses you need to execute your outreach campaign while maintaining high deliverability and avoiding spam filters. It balances volume needs with safety limits.

Why multiple mailboxes

Volume distribution

Spreading emails across addresses keeps each under spam detection thresholds.

Risk mitigation

If one mailbox has issues, others remain unaffected and operational.

Scalability

More mailboxes enable higher volume while maintaining deliverability.

Best practices

Warmup period

New mailboxes need 14-30 days of gradual volume increase.

Daily limits

Stay under 15-20 emails per mailbox per day for safety.

Domain diversity

Use multiple domains to further distribute sending reputation.

Start sending with confidence

Get the exact number of mailboxes you need with guaranteed deliverability