Free Cold Email Warm-Up & Ramp-Up Schedule Calculator
Calculate the exact daily sending schedule, 21-day ramp-up curve, and required mailbox count to reach your outbound sales lead targets safely.
How many cold emails do you want to send per day?
Recommended Inboxes
18 Mailboxes
Safe cap: 35 cold emails / inbox
Recommended Domains
6 Domains
Max 3 inboxes per secondary domain
Estimated Monthly Leads
13,200
Calculated over 22 business days
21-Day Safe Sending Ramp Schedule
Burn-Protection Protocol| Timeline | Emails / Mailbox / Day | Total Daily Outbound | Domain Health Risk |
|---|---|---|---|
| Day 1 | 2 emails | 36 emails | Safe (0% Burn) |
| Day 3 | 5 emails | 90 emails | Safe (0% Burn) |
| Day 5 | 10 emails | 180 emails | Safe (0% Burn) |
| Day 7 | 15 emails | 270 emails | Safe (0% Burn) |
| Day 10 | 20 emails | 360 emails | Safe (0% Burn) |
| Day 14 | 28 emails | 504 emails | Safe (0% Burn) |
| Day 18 | 32 emails | 576 emails | Safe (0% Burn) |
| Day 21 | 35 emails | 600 emails | Safe (0% Burn) |
⚡Skip the 21-Day Waiting Period
WarmedInboxes delivers pre-warmed business mailboxes for just $4.00/mo so you can launch immediately.
Why Cold Outbound Teams Use Our Free Warm-Up Calculator
Interactive daily send target slider
Optimal mailbox count recommendations
21-day ramp-up schedule generator
Email Deliverability Standards (US & UK Outbound Guidelines)
In February 2024, Google Workspace and Yahoo introduced strict anti-spam enforcement rules that mandate proper SPF, DKIM, and DMARC authentication for all outbound mailboxes. If your DNS records have syntax errors or exceed the 10-lookup threshold, incoming mail servers will silently route your cold outreach into the Spam folder or reject connections entirely.
Requires valid physical postal address in signatures, accurate From header identification, and clear opt-out mechanics.
Permits B2B outreach under legitimate interest when targeted to relevant corporate decision-makers with authenticated sender identity.
Frequently Asked Questions About Warm-Up Calculator
How many cold emails should I send per mailbox per day?
The golden rule for maximum deliverability is 30 to 40 cold emails per mailbox per day. To send 1,000 emails per day, you should distribute volume across 25 to 30 mailboxes.
How long does it take to warm up a fresh mailbox?
From scratch, safe warmup takes 14 to 21 days. With WarmedInboxes, our mailboxes come pre-warmed so you skip this waiting period completely.
Need Pre-Warmed Mailboxes Ready to Send?
Get fully authenticated, pre-warmed business inboxes on your own domains with dedicated US & UK IPs for just $4.00/mailbox/month.