Cold Email Infrastructure Planner
Enter your target daily send volume to get your exact domain count, inbox count, warmup schedule, monthly cost breakdown, and a downloadable DNS setup checklist.
Quick Answer
How many domains and inboxes do I need for cold email?
To send 500 cold emails per day safely, you need approximately 6 domains and 17 to 18 inboxes (at 30 emails per inbox per day and 3 inboxes per domain). To send 1,000 emails per day, you need 12 domains and 34 inboxes. Always warm up each inbox for 4 weeks before sending at full volume. Use separate domains from your primary business domain to protect your main domain reputation.
Sending Goals
Campaign type
For cold outreach, stay at or below 30-40 emails/inbox/day. Personalized openers improve deliverability.
Infrastructure Settings
Safe range is 25-40 per day
Max 3 recommended to protect domain reputation
Domain age requirement
Email service provider
Warmup Settings
Warmup tool
Start sending after warmup
Campaigns start after full warmup
Domain Costs
Domain registrar
Domains Needed
6
3 inboxes per domain
Total Inboxes
18
Google Workspace
Monthly Cost
$149.99
All infrastructure combined
Cost per 1,000 Emails
$13.64
At 22 working days
Monthly Cost Breakdown
| Component | Qty | Unit Cost | Monthly |
|---|---|---|---|
| Domains (Namecheap) | 6 | $9.98/yr | $4.99 |
| Inboxes (Google Workspace) | 18 | $6.00/mo | $108.00 |
| Warmup (Instantly.ai) | 1 | $37.00 flat | $37.00 |
| TOTAL | $149.99 | ||
Warmup Schedule
Full capacity: Jul 27, 202617% of full capacity
33% of full capacity
67% of full capacity
100% of full capacity
DNS Setup Checklist
Configure these records on each of your 6 domains
Authorize Google Workspace to send on behalf of your domain
Cryptographic signature for email authentication
Start with p=none for monitoring, upgrade to p=quarantine after 30 days
Point to Google Workspace mail servers
Optional: custom domain for link tracking (reduces spam score)
ESP Cost Comparison
At 18 inboxes
| Provider | Per Inbox | Monthly Total |
|---|---|---|
| Google Workspace SelectedBest deliverability | $6.00/mo | $108.00 |
| Microsoft 365 Best deliverability | $6.00/mo | $108.00 |
| Zoho Mail | $1.00/mo | $18.00 |
| Namecheap Private Email | $0.99/mo | $17.82 |
| SMTP self-hosted Cheapest | $0.10/mo | $1.80 |
About this tool
Cold email deliverability depends heavily on infrastructure setup. Sending too much volume from too few domains or unewarmed inboxes triggers spam filters at Gmail, Outlook, and other providers. This planner takes your target daily send volume and works backward to calculate the exact number of domains and inboxes you need, what it will cost, and how long your warmup period must be before you can send at full volume.
Most cold email guides give rough rules of thumb like "use 3 inboxes per domain." This tool makes those rules precise and personalized: it factors in your ESP pricing, domain registrar cost, warmup tool choice, and working days per month to produce a complete infrastructure plan with a downloadable DNS checklist. Whether you are a solo founder starting your first campaign or an agency managing infrastructure for dozens of clients, the output gives you a ready-to-execute setup checklist.
How it works
- 1
Inbox and domain count
Divides your target daily send volume by emails per inbox per day to get inboxes needed, then divides by inboxes per domain to get domain count. Rounds up at every step to ensure you have enough capacity.
- 2
Monthly cost calculation
Adds three cost buckets: ESP cost (total inboxes times monthly price), domain cost (total domains times annual price divided by 12), and warmup tool cost (flat fee or per-inbox depending on tool). Produces a total monthly cost and cost per 1,000 emails sent.
- 3
Warmup schedule
Generates a week-by-week warmup ramp starting at 5 emails per inbox per day in week 1, doubling each week up to your target limit. Shows total daily capacity at each stage and calculates your full-capacity date from today.
- 4
DNS checklist
Lists all required DNS records per domain (SPF, DKIM, DMARC, MX) with status labels. The downloadable CSV generates one row per domain with placeholders you fill in with actual domain names and your ESP's specific record values.
Cold email sending limits reference
Assumes 30 emails/inbox/day, 3 inboxes/domain, Google Workspace, Instantly warmup tool, Namecheap domains
| Daily volume | Domains needed | Inboxes needed | Est. monthly cost |
|---|---|---|---|
| 100/day | 2 | 6 | ~$75/mo |
| 250/day | 3 | 9 | ~$95/mo |
| 500/day | 6 | 18 | ~$150/mo |
| 1,000/day | 12 | 36 | ~$265/mo |
| 2,500/day | 28 | 84 | ~$565/mo |
| 5,000/day | 56 | 168 | ~$1,090/mo |
Standard warmup schedule reference
| Week | Emails/inbox/day | Total/day (10 inboxes) | Notes |
|---|---|---|---|
| Week 1 | 5 | 50 | Build reputation gently with high-quality warmup seeds |
| Week 2 | 10 | 100 | Increase engagement signals, monitor spam rates |
| Week 3 | 20 | 200 | Approaching normal operational limits |
| Week 4 | 30-40 | 300-400 | Ready for real campaigns at full volume |
Frequently asked questions
How many domains do I need for cold email?⌄
How many emails can I send per inbox per day safely?⌄
How long does email warmup take?⌄
What is the best email service provider for cold email?⌄
Do I need separate domains for cold email?⌄
What DNS records do I need for each cold email domain?⌄
How much does cold email infrastructure cost per month?⌄
What warmup tool should I use for cold email?⌄
Related guides
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