How many mailboxes you need

Work out how many mailboxes and domains you need for your target daily volume — without burning reputation.

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Mailboxes / inputvolumefig.

Daily emails you want to sendEmails per mailbox / day≤ 50 recommended

Mailboxes / resultsetupfig.

Mailboxes

Domains

Emails per domain / day143

Monthly volume30,000

Recommended warmup~8 weeks

Mailboxes per domain3

Infrastructure

Spread volume, protect reputation

Keeping each inbox to ~50 cold emails a day protects deliverability and avoids provider throttling.

Spread mailboxes across domains — roughly three per domain — so one issue can't sink everything.

Every new mailbox needs ~8 weeks of warmup before it carries full cold-email volume.

FAQ4 entries

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For cold outreach, keep it around 50 emails per mailbox per day. Higher volumes from a single inbox quickly trigger spam filters.

Divide your target daily volume by ~50. The calculator does this and also tells you how many domains to spread them across.

Spreading mailboxes across domains (about 3 per domain) limits blast radius — if one domain's reputation dips, the rest keep sending.

Yes. Plan ~8 weeks of gradual warmup per new mailbox before pushing full volume, or use an automated warmup network.

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