Three inboxes per domain and 40 cold emails per inbox per day. That gives about 120 a day per domain. Buy more domains, not more inboxes per domain.
Why three
Reputation is scored per domain and per inbox. If one domain gets flagged, every inbox on it is affected. Three keeps the blast radius small and keeps the per-domain volume looking like a small company rather than a sending farm. Five is the upper bound some teams use on aged domains; past that, Google Workspace itself starts to notice.
Why 40
Google Workspace allows far more, but allowed is not safe. Across teams running thousands of inboxes, 30 to 40 cold emails a day per inbox with warmup running is where placement holds. At 50 and above, placement decays over weeks even with clean copy. Transactional and reply mail from the same inbox does not count toward this.
When to break the rules
- Domain older than six months with clean Postmaster data: 50 per inbox is usually fine.
- Domain under 30 days: halve everything. 20 a day, two inboxes, warmup for three weeks.
- After any spike in bounces or complaints: drop to 10 a day for a week before ramping back.
Use the volume planner to turn a target into inboxes, domains and cost.
Turn a daily volume into inboxes, domains, warmup ramp and monthly cost. Click any domain to see its inboxes.
Questions
Can I send 100 cold emails a day from one inbox?
You can, and placement will decay within weeks. 40 is the safe ceiling; buy more inboxes instead.
Do replies count toward the daily limit?
No. Replies and normal correspondence help reputation. The limit is for cold first touches.