Guide
How Many Cold Emails Per Day? The Safe Sending Math
The per-mailbox limit that keeps cold email in the inbox: 8–10 per user per day, and the exact math from daily target to users, domains and cost — with a worked 1,000-a-day example.
The short answer
8–10 cold emails per mailbox per day. That is the volume that keeps warmed mailboxes healthy over months, not weeks. You can push toward 15 with strong engagement; below 5 you are wasting infrastructure. Everything else in cold email volume planning is multiplication from this number.
The math, worked: 1,000 emails a day
Users needed: 1,000 ÷ 10 per user = 100 users. Domains at 2 users per domain: 50 domains. Microsoft tenants at 25 users each: 4 workspaces. That is the whole calculation — the same arithmetic our Capacity Co-pilot runs, deterministically, when it prices a build.
Why not 50 emails from 20 mailboxes? Because provider filters profile per-mailbox behavior: sudden volume from a small pool looks like what it is. Many mailboxes at human volume beats few mailboxes at machine volume, every time.
New mailboxes don't start at 10
A fresh mailbox starts at its provider's floor — a handful a day — and ramps over two to three weeks. During ramp, warmup traffic and campaign traffic share the cap. Plan capacity on steady-state numbers and let the ramp run; forcing week-three volume in week one is the most common self-inflicted deliverability wound.
Questions, answered straight
Does the 8–10 limit include follow-ups?
Yes — it is total outbound per mailbox per day. Sequences with two or three steps mean your NEW-lead rate is a fraction of total sends; plan lists accordingly.
Can I send more from Google than Microsoft?
Provider caps differ technically, but filter behavior punishes cold volume similarly. Keep the same 8–10 discipline on both; vary by observed engagement, not by provider marketing.
What if I need 5,000 a day?
Same math, bigger fleet: ~500 users across ~250 domains. At that scale the operational load (DNS drift, credential management, replacing burned domains) is the real cost — which is why we automated it.
Turn your target into an exact build
Enter your daily capacity — the calculator returns users, domains and price to the cent.
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