Cold email inbox calculator
How many inboxes and domains do you need, and what will they cost? Enter your daily volume. We size the setup and price it against every provider we track, respecting each plan's minimum order and sending cap.
Cheapest providers for this setup
| Provider | Type | Inboxes | Mailboxes / mo | Domains / mo | Total / mo | Notes |
|---|
Monthly list prices checked 2026-10-23. Domains are priced at the provider's own domain price ÷ 12 when published, otherwise at a $10.46/yr reference .com. Flat-rate and tiered plans (Inframail, Mission Inbox, Winnr, Mailreef) aren't priced per inbox and are left out. Compare them in the main table. Excludes your sending tool, see cold email software pricing.
How the calculator works
Inboxes = emails per day ÷ emails per inbox per day, rounded up. If a plan caps sends per inbox below your setting (some cheap plans allow only 3–15 a day), we use the cap, so you need more inboxes on that plan. If a plan has a minimum order, we round up to it.
Domains = inboxes ÷ inboxes per domain, rounded up. Cost = inboxes × the plan's monthly per-inbox list price + domains × yearly domain price ÷ 12.
Quick reference (Google inboxes, 25/inbox/day, 3 per domain)
| Emails / day | Inboxes | Domains | Cheapest Google / mo | Workspace direct / mo |
|---|---|---|---|---|
| 100 | 4 | 2 | $13.74 InboxKit | $29.74 |
| 500 | 20 | 7 | $66.10 InboxKit | $146.10 |
| 1,000 | 40 | 14 | $132.20 InboxKit | $292.20 |
| 3,000 | 120 | 40 | $394.87 InboxKit | $874.87 |
Before you send: warm new inboxes for 2–3 weeks, verify your list (verification tools compared), and keep each inbox well under its limit.
Frequently asked questions
How many inboxes do I need for cold email?
Divide the emails you want to send per day by what each inbox can safely send. At a common 25 cold emails per inbox per day, 500 emails/day needs 20 inboxes and 1,000 emails/day needs 40 inboxes. Some cheap plans cap each inbox lower (e.g. 3–15 a day), which means you need more inboxes.
How many domains do I need for cold email?
Most senders put 2–3 inboxes on each secondary domain. At 3 per domain, 20 inboxes need 7 domains and 40 inboxes need 14 domains. Never send cold email from your main company domain.
What does it cost to send 100 cold emails a day?
About 4 inboxes on 2 domains at 25 emails per inbox per day. At the cheapest Google inbox list price we track (InboxKit), that's about $13.74/mo including domains, vs $29.74/mo buying Google Workspace direct. Prices checked 2026-10-23.
What does it cost to send 500 cold emails a day?
About 20 inboxes on 7 domains at 25 emails per inbox per day. At the cheapest Google inbox list price we track (InboxKit), that's about $66.10/mo including domains, vs $146.10/mo buying Google Workspace direct. Prices checked 2026-10-23.
What does it cost to send 1,000 cold emails a day?
About 40 inboxes on 14 domains at 25 emails per inbox per day. At the cheapest Google inbox list price we track (InboxKit), that's about $132.20/mo including domains, vs $292.20/mo buying Google Workspace direct. Prices checked 2026-10-23.
What does it cost to send 3,000 cold emails a day?
About 120 inboxes on 40 domains at 25 emails per inbox per day. At the cheapest Google inbox list price we track (InboxKit), that's about $394.87/mo including domains, vs $874.87/mo buying Google Workspace direct. Prices checked 2026-10-23.
How long do new inboxes need to warm up?
Plan on 2–3 weeks of warmup at low volume before sending cold campaigns at full volume, so order inboxes before you need them.