Free tool
Sending capacity calculator
Type how many cold emails you want to send each day. We tell you how many domains and inboxes you need, what they cost, and when you can start.
- Free, and you do not sign up
- Uses the 2026 safe limits
- Warmup dates included
- Share the plan as a link
To send 500 cold emails a day
Buy 4 domains, and make 12 inboxes.
- Domains
- 4
- Inboxes
- 12
- Emails for each inbox a day
- 42
- Cost
- $88 a month
Your setup
- Domain 13 inboxes
- Domain 23 inboxes
- Domain 33 inboxes
- Domain 43 inboxes
Each inbox sends about 42 cold emails a day. Your sending tool spreads each campaign across all of them. You also have room for 40 more emails a day.
When you can send
If you buy the domains today, you can start small on Dec 9, and send 500 a day from about Dec 30.
Do you not want to wait? We also set you up with pre-warmed inboxes. They already have a sending history, so you can start your campaigns much sooner.Ask about pre-warmed inboxes
- Buy and set upNov 4 to Nov 18Buy the domains, add SPF, DKIM and DMARC, and make the inboxes. Then wait.
- Warm upNov 18 to Dec 9A warmup tool sends and answers emails for each inbox, so email providers start to trust it.
- Grow to full volumeDec 9 to Dec 30Start campaigns at 5 to 10 emails a day for each inbox, and add a little each week.
Emails a day, week by week
- 120Week 5
- 247Week 6
- 373Week 7
- 500Week 8
Change the rules
We use the safe limits from our deliverability guide. You can change them, but the safe range is 40 to 50 emails for each inbox, and 2 to 3 inboxes for each domain.
The prices are our estimates for a .com domain and a Google Workspace or Microsoft 365 inbox. Type your own prices.
How we work out your setup
We use two simple rules. Each inbox sends 40 to 50 cold emails a day, and each domain holds 2 or 3 inboxes. Here is the math for 500 emails a day.
-
You want to send
500
Cold emails each day.
-
Each inbox sends up to
45
The safe range is 40 to 50 a day.
-
So you need
12 inboxes
500 divided by 45, rounded up.
-
Each domain holds 3
4 domains
12 inboxes divided by 3.
These rules come from our 2026 deliverability guide. It also covers warmup and inbox rotation in more detail.
Quick table
Find your daily volume, and read across. We use 45 emails for each inbox and 3 inboxes for each domain.
Why you need more than one inbox
-
Email providers watch each inbox
If one inbox sends too much, Gmail and Outlook start to send its email to spam.
So you keep each inbox under 50 cold emails a day, and you add more inboxes when you want to send more.
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You must stay under two limits
Keep spam reports under 0.3% and bounces under 2%.
If you go over, Gmail, Yahoo and Outlook slow down or block your email. Small daily volumes make it easier to stay under.
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Separate domains keep your main domain safe
Your team uses your main domain for normal work email.
If a sending domain gets into trouble, you can stop using it. Your main domain stays clean.
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New inboxes need time
A new inbox has no history, so email providers do not trust it yet.
Plan 5 to 8 weeks from buying a domain to full volume. The calculator shows you the dates. If you cannot wait, we also offer pre-warmed inboxes.
Questions
How many cold emails can one inbox send each day?
Send 40 to 50 cold emails a day from each inbox. If you send more, spam reports and bounces go up, and email providers start to block that inbox. Warmup emails are extra, and your warmup tool handles them.
How many inboxes can I put on one domain?
Put 2 or 3 inboxes on each domain. If one domain gets a bad name with email providers, only those few inboxes stop working, and the rest of your campaign keeps going.
Why can I not send cold email from my main domain?
Some people will mark your cold email as spam, even when it is good. If that happens on your main domain, your normal work email can start to go to spam too. So buy separate domains for cold email, for example a .com that looks like your brand name.
How long does it take before I can send?
About 5 to 8 weeks. Wait about 2 weeks after you buy a domain. Then warm up each inbox for at least 3 weeks. Start with 5 to 10 emails a day for each inbox, and add a little each week until you get to full volume.
Can I skip the warmup?
Yes, with pre-warmed inboxes. These inboxes already have a sending history, so email providers trust them sooner, and you can start your campaigns much faster. We set up pre-warmed inboxes for clients who need to start soon. Book a call, and we tell you which option fits your plan.
What is inbox rotation?
Your sending tool spreads each campaign across all your inboxes, so each inbox stays under its daily limit. If one inbox has a problem, the others keep sending. Most cold email tools do this for you.
How much does this setup cost?
A .com domain costs about $12 a year, and a Google Workspace or Microsoft 365 inbox costs about $7 a month. So 12 inboxes on 4 domains cost about $88 a month. Open “Change the rules” in the calculator to use your own prices.
Can you set this up for me?
Yes. We buy the domains, add the records, make the inboxes and warm them up. If you need to start soon, we use pre-warmed inboxes. Then we write and run your campaigns. Book a call, and we plan your setup with you.