Inframail
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How to calculate your email sending capacity and choose the right plan

Overview

You'll learn how to calculate exactly how many domains and inboxes you need based on your daily campaign email volume, and which Inframail plan fits your sending requirements.

Prerequisites

  • Understanding of your target daily or monthly campaign email volume

  • Knowledge of your cold email outreach goals

Understanding the formula

Email sending capacity on Inframail is calculated using a simple formula based on safe sending practices:

Safe sending limit per inbox

Each email inbox can send up to 50 emails per day. However, we recommend 40 emails per inbox per day for optimal deliverability and to avoid spam filters.

Pro tip: The 40-email recommendation includes both warmup emails and live outbound emails. When we say "total emails," this breakdown is typically 70% warmup emails and 30% campaign emails. For example, if each inbox is sending 40 total emails per day, 28 of those would be warmup emails and 12 would be campaign emails.

For safe deliverability, we recommend 3-5 email inboxes per domain. You can create up to 10 inboxes per domain, but staying within the 3-5 range helps maintain better sender reputation.

The calculation formula

Step 1: Calculate total inboxes needed

Total Inboxes = Daily Campaign Email Volume ÷ 12 campaign emails per inbox

Step 2: Calculate domains needed

Total Domains = Total Inboxes ÷ 3 inboxes per domain

Round up to the nearest whole number for both calculations.

Calculation examples

Example 1: Sending 2,500 campaign emails per day

  1. Calculate inboxes: 2,500 ÷ 12 = 208.3 inboxes (round up to 209)

  2. Calculate domains: 209 ÷ 3 = 69.7 domains (round up to 70)

  3. Daily capacity verification: 70 domains × 3 inboxes × 12 campaign emails = 2,520 campaign emails/day ✓

Remember: If you're sending 40 emails per day from each inbox, 70% is for warmup and 30% is for campaign emails. So 12 campaign emails out of the 40 total.

Result: You need 70 domains with 3 inboxes each (210 total inboxes) to safely send 2,500 campaign emails per day.

Example 2: Sending 5,000 campaign emails per day

  1. Calculate inboxes: 5,000 ÷ 12 = 416.7 inboxes (round up to 417)

  2. Calculate domains: 417 ÷ 3 = 139 domains

  3. Daily capacity verification: 139 domains × 3 inboxes × 12 campaign emails = 5,004 campaign emails/day ✓

Remember: If you're sending 40 emails per day from each inbox, 70% is for warmup and 30% is for campaign emails. So 12 campaign emails out of the 40 total.

Result: You need 139 domains with 3 inboxes each (417 total inboxes) to safely send 5,000 campaign emails per day.

Example 3: Sending 10,000 campaign emails per day

  1. Calculate inboxes: 10,000 ÷ 12 = 833.3 inboxes (round up to 834)

  2. Calculate domains: 834 ÷ 3 = 278 domains

  3. Daily capacity verification: 278 domains × 3 inboxes × 12 campaign emails = 10,008 campaign emails/day ✓

Remember: If you're sending 40 emails per day from each inbox, 70% is for warmup and 30% is for campaign emails. So 12 campaign emails out of the 40 total.

Important: With 834 inboxes, you'll need multiple dedicated IPs to distribute your sending infrastructure safely. The Agency Pack (3 IPs) is strongly recommended for this volume.

Choosing the right Inframail plan

Inframail offers two main subscription plans based on your sending volume and infrastructure needs:

Unlimited Plan - $129/month

Best for: Small agencies and businesses (∼50+ meetings/month)

What's included:

  • 10 FREE domains included

  • 1 Dedicated US IP ready-to-go

  • Unlimited Email Inboxes

  • Unlimited Domain Setups Per Day

  • FREE automation to setup emails

  • Priority Support

  • API Access

Agency Pack - $327/month

Best for: Growing agencies and high-volume senders (∼200+ meetings/month)

What's included:

  • 20 FREE domains included

  • 3 Dedicated US IPs ready-to-go

  • Unlimited Email Inboxes

  • Unlimited Domain Setups Per Day

  • FREE automation to setup emails

  • 1-on-1 Deliverability Consultant

  • Priority Support

  • API Access

Annual plans (30% discount)

Both plans are available with annual billing at a 30% discount, plus additional free domains and migrations:

  • Annual Unlimited: $90.30/month (billed annually) — 20 FREE domains + 70 FREE domain migrations

  • Annual Agency Pack: $228.90/month (billed annually) — 60 FREE domains + 100 FREE domain migrations

Quick reference: General guideline for volume to plan mapping

Daily Campaign Email Volume

Inboxes Needed

Domains Needed

Recommended Plan

1,000-2,000

84-167

28-56

Unlimited Plan ($129/mo)

2,000-5,000

167-417

56-139

Unlimited Plan ($129/mo)

5,000-10,000

417-834

139-278

Agency Pack ($327/mo)

10,000-18,000

834-1,500

278-500

Agency Pack ($327/mo)

18,000+

1,500+

500+

Multiple Agency Packs

Domain setup and free domains

Both Inframail plans include unlimited domain setups per day, so you can configure all your domains in one session without daily limits.

Free domains included

  • Unlimited Plan (monthly): 10 FREE domains

  • Unlimited Plan (annual): 20 FREE domains + 70 FREE domain migrations

  • Agency Pack (monthly): 20 FREE domains

  • Agency Pack (annual): 60 FREE domains + 100 FREE domain migrations

Note: Additional domains beyond the free included amount can be purchased at $16.44/year for .com domains or $9.44/year for .info domains.

Additional costs to consider

Beyond your monthly subscription, you'll need to account for domain costs:

Domain options

  • Create new domains: $16.44/year for .com domains or $9.44/year for .info domains

  • Migrate existing domains: $5 per domain (one-time fee)

  • Domain renewals: $16.44 for .com domains

Domain purchase limits: You can purchase up to 5 new domains every 24 hours through the Create tab. For domain migrations, you can migrate 5 domains in the first 24 hours, then up to 20 domains every 24 hours afterward.

Total cost example

For sending 2,500 campaign emails/day with 70 new .com domains on the Unlimited Plan:

  • Monthly subscription: $129 (Unlimited Plan)

  • Free domains included: 10 domains (included with plan)

  • Additional domains needed: 60 domains × $16.44 = $986.40

  • Total first-year cost: ($129 × 12) + $986.40 = $2,534.40

  • Monthly average (year 1): ~$211/month

Best practices for scaling

Start conservative

Begin with 3 inboxes per domain and gradually add more up to 5 as you scale. This gives you room to grow while maintaining deliverability.

Distribute across IPs

For the Agency Pack with 3 IPs, distribute your domains evenly across all three IPs. For example, with 84 domains, allocate 28 domains per IP.

Best practice: Keep 300-400 inboxes per dedicated IP for optimal deliverability and sender reputation management.

Account for warmup

Remember that your warmup emails count toward your daily sending limit. The 40 emails per inbox includes both warmup and campaign emails, with a typical split of 70% warmup (28 emails) and 30% campaign (12 emails). This means your actual campaign capacity is based on the 30% allocation, not the full 40 emails.

Plan for growth

If you anticipate scaling your outreach, consider starting with the Agency Pack to avoid the need to upgrade and reconfigure your infrastructure later.

When to upgrade

You should upgrade from Unlimited to Agency Pack when:

  • You're approaching 150+ inboxes on a single IP

  • You need more free domains (Agency Pack includes 20 free domains vs. 10 for Unlimited)

  • You need better IP isolation for different campaigns or clients

  • You want 1-on-1 deliverability consulting included

Easy upgrades: You can upgrade or downgrade your plan at any time through your subscription page. Inframail calculates prorated charges automatically.

Verify your setup

After setting up your infrastructure, verify your capacity:

  1. Count your total active domains

  2. Count total inboxes per domain (should be 3-5)

  3. Calculate: Domains × Inboxes per domain × 12 campaign emails = Daily campaign capacity

  4. Ensure your daily campaign sending stays within this capacity

What's next

  • Ready to get started? Sign up for Inframail

  • Learn how to set up your domains and inboxes efficiently

  • Understand email warmup best practices

  • Explore integration with cold email platforms like Instantly, Smartlead, or ReachInbox

Getting help

If you're unsure which plan is right for your needs or need help with capacity planning:

  • Contact support at [email protected]

  • Include your target daily/monthly campaign email volume

  • Mention any specific infrastructure requirements or constraints

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