Cold Email ROI Calculator
Now that you know the infrastructure, see whether the campaign actually pays off.
Cold Email Inbox & Domain Calculator
Enter the daily volume you want to send and see exactly how many inboxes and domains you need to hit it safely, your real sending capacity, and what the infrastructure costs each month.
Free · no sign-up · runs in your browserSome links are affiliate links. If you sign up through them we may earn a commission at no extra cost to you. It never changes what the calculator shows.
Editorial note: This tool is for informational and educational purposes only and is not professional advice. The defaults reflect common cold email deliverability practice for 2026 (roughly 30 sends per inbox per day, about 3 inboxes per domain), but safe limits shift with your warmup, list quality, and email provider. Treat the output as a planning estimate and edit every field to match your own setup.
How cold email infrastructure works
Cold email deliverability depends less on your copy than on how you spread sending across mailboxes and domains. Push too much volume through one inbox and providers throttle you or route messages to spam. The way around that is to spread volume thin: many inboxes, each sending a small daily amount, across several domains so no single domain carries the whole load.
Three numbers drive the plan. The safe daily send per inbox (commonly 30 to 50 once an inbox is warmed), the number of inboxes you host on each domain (often around three), and the total daily volume you are aiming for. From those, the inbox and domain counts fall out directly, and so does the monthly bill.
The math behind the numbers
- Inboxes needed = daily send target divided by safe sends per inbox, rounded up.
- Domains needed = inboxes divided by inboxes per domain, rounded up.
- Monthly capacity = inboxes times safe daily send, times the business days you send (about 22).
- Monthly cost = inbox count times price per inbox, plus domain count times the monthly share of the domain price.
How to protect deliverability
- Warm every inbox first. Give each mailbox about two weeks of gradual, automated warmup before real sends, then ramp volume slowly.
- Authenticate every domain. Set up SPF, DKIM, and DMARC before the first campaign, or inboxing collapses regardless of volume.
- Keep cold sending off your main domain. Use separate secondary domains so a spam hit never touches your primary company email.
- Clean the list. Verify addresses before sending, because bounces damage sender reputation faster than volume does.
Once the infrastructure is sized, model whether the campaign pays off with the Cold Email ROI Calculator, see the one-time build cost in our cold email setup cost breakdown, or match yourself to a platform with the Which Cold Email Tool quiz.
Frequently asked questions
How many inboxes do I need for cold email?
Divide your target daily send by the safe volume per inbox (commonly 30 to 50 a day once warmed). To send 1,000 a day at 30 per inbox, you need about 34 inboxes. Enter your own target above to size it exactly.
How many email accounts should I have per domain?
About three inboxes per domain is common, so no single domain carries too much sending. More domains means less risk that one reputation problem takes down everything.
How many cold emails can I send per day?
Per inbox, keep it to roughly 30 to 50 a day once warmed, and far less in the first two weeks. Total daily volume is that per-inbox limit times the number of inboxes, so you scale by adding inboxes, not by sending more from each.
How much does cold email infrastructure cost?
Mostly mailboxes plus domains. At a few dollars per inbox each month and cheap domains, a setup sending 1,000 a day runs on the order of $150 a month before your sending platform. Reseller mailboxes cost less than Google Workspace or Microsoft 365 seats.
Methodology. Inboxes needed = ceil(daily target ÷ safe sends per inbox). Domains needed = ceil(inboxes ÷ inboxes per domain). Safe daily capacity = inboxes × safe sends per inbox. Monthly capacity assumes about 22 business sending days. Monthly cost = inboxes × price per inbox per month + domains × (domain price per year ÷ 12). Warmup time and sending platform fees are not included.