Cold email glossary

What is Daily sending limit (per mailbox)?

The maximum cold emails a single mailbox sends per day — 20 to 50 in practice, far below the provider's technical cap.

Google Workspace allows 2,000 messages a day per user and Exchange Online allows 10,000 recipients, but reputation gives out long before those caps. Sustainable cold email volume is 20–30 a day per warmed mailbox, up to 50 on an aged domain with a clean list. To send more, add mailboxes and domains rather than raising per-mailbox volume.

Related terms

GlossarySend gap (throttling)The minimum time between two emails from the same mailbox, randomised so sends don't fall on a fixed interval.GlossaryMailbox rotation (inbox rotation)Spreading one campaign's sends across many connected mailboxes so no single sender exceeds its daily limit.GlossaryNew leads per day (ramp)A cap on how many new prospects enter a campaign each day, so a list is worked in gradually rather than blasted on launch.

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