Self-hosted email costs $5-40/month in direct infrastructure costs (VPS, domain, monitoring tools) regardless of sending volume. The hidden cost is your time — budget 2-4 hours/month for maintenance at your hourly rate. At 100K emails/month, self-hosted saves ~$5-15/month vs. Mailgun. At 500K/month, savings reach $30-100/month. At 1M+/month, savings are $100-500/month. Below 50K/month, the time cost usually exceeds the savings.
Self-Hosted SMTP Cost Calculator: What You'll Actually Spend
Self-Hosted SMTP Costs: The Full Picture
Self-hosted email marketing always promises cost savings. And it delivers — at scale. But most calculations ignore the hidden costs that make self-hosting more expensive than expected below certain volume thresholds.
This guide gives you the real numbers so you can make an informed decision. Also see is self-hosting worth it and when to self-host.
Direct Infrastructure Costs
VPS (Monthly)
| Provider | Tier | RAM | Disk | Monthly Cost |
|---|---|---|---|---|
| Hetzner CAX11 | ARM | 4 GB | 40 GB | ~$4 |
| Hetzner CX22 | x86 | 4 GB | 40 GB | ~$5 |
| OVH Starter | x86 | 2 GB | 40 GB | ~$4 |
| DigitalOcean | Basic | 2 GB | 50 GB | $12 |
| Vultr | Regular | 2 GB | 55 GB | $12 |
For Mailcow (recommended for most users), the Hetzner CX22/CAX11 at $4-5/month handles up to ~50K emails/day comfortably.
For high volume (100K+/day), step up to 8GB RAM: Hetzner CX32 at ~$9/month.
Domain & DNS
| Item | Cost |
|---|---|
| Domain registration | $10-15/year (~$1/month) |
| DNS hosting | Free (Cloudflare) or included with registrar |
| SSL certificate | Free (Let's Encrypt) |
Monitoring Tools
| Tool | Free Tier | Paid Tier |
|---|---|---|
| Google Postmaster Tools | Free | N/A |
| MXToolbox Monitoring | 1 IP/domain free | $100/year |
| UptimeRobot | 50 monitors free | $7/month |
| Microsoft SNDS | Free | N/A |
Backup Storage
| Service | Cost |
|---|---|
| Hetzner Storage Box | $4/month (100 GB) |
| Backblaze B2 | $0.005/GB/month |
| AWS S3 (infrequent) | $0.0125/GB/month |
Total Direct Cost
| Setup | Monthly Cost |
|---|---|
| Minimal (Hetzner + free monitoring) | $5-7 |
| Standard (Hetzner + MXToolbox + backup) | $15-20 |
| Premium (larger VPS + monitoring + backup) | $25-40 |
Time Costs (The Hidden Number)
This is where most calculations fail. Your time has value.
Monthly Time Budget
| Task | Healthy Server | Problematic Server |
|---|---|---|
| Updates & patches | 30 min | 30 min |
| Queue monitoring | 15 min | 1-2 hours |
| Blacklist checks | 15 min | 2-4 hours (delisting) |
| Log review | 15 min | 1-2 hours |
| Troubleshooting | 0 | 2-8 hours |
| Total | 1-2 hours | 6-16 hours |
Time Cost Calculation
Monthly time cost = Hours/month x Your hourly rate
Example (stable server):
2 hours x $75/hour = $150/month in time
Example (problematic server):
8 hours x $75/hour = $600/month in time
For a founder or senior engineer at $100-200/hour, even 2 hours/month adds $200-400 in opportunity cost.
Self-Hosted vs. ESP Cost by Volume
Cost at 50K Emails/Month
| Option | Monthly Cost | Including Time |
|---|---|---|
| Self-hosted (Hetzner) | $7 | $157 ($75/hr x 2hrs) |
| Mailgun (Foundation) | $35 | $35 |
| SendGrid (Essentials) | $20 | $20 |
| AWS SES | $5 | $5 |
Winner at 50K: AWS SES or SendGrid. Self-hosted costs more when you include time.
Cost at 200K Emails/Month
| Option | Monthly Cost | Including Time |
|---|---|---|
| Self-hosted (Hetzner) | $10 | $160 |
| Mailgun (Foundation) | $75 | $75 |
| SendGrid (Pro) | $90 | $90 |
| AWS SES | $20 | $20 |
Winner at 200K: AWS SES for pure cost. Self-hosted wins only if you value time at under $30/hour.
Cost at 1M Emails/Month
| Option | Monthly Cost | Including Time |
|---|---|---|
| Self-hosted (Hetzner) | $15 | $165 |
| Mailgun (Scale) | $300+ | $300+ |
| SendGrid (Pro) | $450+ | $450+ |
| AWS SES | $100 | $100 |
Winner at 1M: Self-hosted saves $135-285/month even including time. This is where self-hosting shines.
Cost at 5M Emails/Month
| Option | Monthly Cost | Including Time |
|---|---|---|
| Self-hosted (Hetzner, larger VPS) | $30 | $180 |
| Mailgun (custom) | $1,000+ | $1,000+ |
| SendGrid (custom) | $1,500+ | $1,500+ |
| AWS SES | $500 | $500 |
Winner at 5M: Self-hosted, decisively. Savings of $320-1,320/month.
The Break-Even Formula
Break-even volume = (Self-hosted monthly cost + Time cost) / ESP per-email rate
Example with Mailgun ($0.80/1K):
($15 + $150) / $0.0008 = 206,250 emails/month
Example with SES ($0.10/1K):
($15 + $150) / $0.0001 = 1,650,000 emails/month
Against Mailgun, self-hosted breaks even at ~200K/month. Against SES, it breaks even at ~1.6M/month. The cheaper the ESP, the higher the break-even.
Practitioner note: I always tell clients to include their time at full rate, not zero. "I'll manage it myself" sounds free until you're spending Saturday afternoon debugging a blacklist issue instead of working on revenue-generating activities. If your time is worth $100/hour, you need to be saving at least $200/month to justify the 2 hours of maintenance.
Practitioner note: The clients who save the most on self-hosted are agencies sending 500K-5M emails/month across multiple client domains. Their ESP bills were $500-3,000/month. Self-hosted on Hetzner costs $20-40/month. Even hiring me for $200/month maintenance, they save 70-90%. But they all started at a volume that justified the switch.
If you want help calculating whether self-hosted makes sense for your specific situation, schedule a consultation — I'll model the costs against your current ESP spend and volume.
Sources
- Hetzner: Cloud Pricing
- Mailgun: Pricing
- SendGrid: Pricing
- AWS SES: Pricing
v1.0 · April 2026
Frequently Asked Questions
What's the minimum cost for a self-hosted mail server?
About $7/month: Hetzner CX22 at ~$4/month + domain at ~$1/month + your time. You can run Mailcow or Postal on this and send unlimited emails. MXToolbox free tier handles basic monitoring. But this excludes the value of your maintenance time.
How do I calculate the time cost?
Track hours spent on updates, monitoring, troubleshooting, and blacklist management. For a stable server, expect 1-2 hours/month. For a server with issues, 4-8 hours/month. Multiply by your hourly rate (or what you'd pay a sysadmin: $50-150/hour).
At what volume does self-hosting make sense?
Financially, around 100K-200K emails/month — that's where the savings start exceeding the time cost. Strategically, self-hosting makes sense at any volume if you need full control, data residency, or independence from third-party provider rules.
What costs do people forget to include?
Time for maintenance (the biggest hidden cost), monitoring tools (free or $10-50/month), backup storage ($1-5/month), domain registration ($10-15/year), SSL certificates (free with Let's Encrypt), and the opportunity cost when things break.
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