Warming up
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Every account now comes with a free mailbox — warmed automatically, no domain to buy. See how it works
There's no single official number — Gmail and Microsoft 365 judge volume dynamically against reputation. Here are the safe daily ranges by mailbox age, and how to ramp without tripping spam filters.
A safe cold email volume is 5 to 10 a day for a new mailbox and 40 to 50 a day for a warmed one, whatever your provider allows. Google Workspace permits 2,000 messages a day and Microsoft 365 permits 10,000 recipients a day, but those are technical caps, not safe targets. Reputation throttles you long before them. Below: each provider's published limit, the safe number per mailbox, and how to scale by adding mailboxes instead of pushing one past its ceiling.
| Provider | Published limit | Per message | What it means for cold email |
|---|---|---|---|
| Google Workspace (paid) | 2,000 messages a day per user, up to 3,000 external recipients a day. Trial accounts: 500 messages a day. | Up to 500 external recipients (100 over SMTP) | Far above any safe target. Reputation, not the cap, decides your inbox placement. |
| Microsoft 365 (Exchange Online) | 10,000 recipients a day per mailbox, 30 messages a minute. | Up to 1,000 recipients | The per-minute cap matters for fast automation. Outlook filtering is more sensitive to spikes than to steady volume. |
| Outlook.com (free) | Commonly about 300 recipients a day. New accounts start lower. Microsoft adjusts it dynamically and does not publish an exact figure. | 100 recipients | The weakest base for cold outreach. Bulk sending from a free account can get it restricted or locked. |
| Zoho Mail | 50 to 500 external emails an hour, dynamic with sender reputation. 1,000 an hour internal. | 150 paid, 100 free | Zoho meters by the hour, so a burst can stall even when your daily total is small. |
| Hostinger Titan Email | Free: 50 an hour, 300 a day. Business: 200 an hour, 500 a day. Enterprise: 300 an hour, 1,000 a day. | Per plan | Hostinger's anti-abuse systems can slow bursts even under the daily number. |
| GoDaddy Workspace Email | 500 recipients a day, 300 an hour, 200 a minute. | Per plan | The lowest of the paid providers here. Spread sends across several mailboxes. |
Every one of these is a ceiling on what the provider will accept, not a volume a new sender can use. A mailbox with no history that sends 500 cold emails on day one is blocked or filtered by reputation long before it reaches the platform cap, which is why the safe numbers below are so much lower.
Treat these as ceilings to approach gradually, not day-one targets. A mailbox that jumps straight to 50 sends with zero sending history reads as suspicious regardless of what the provider's raw limit allows.
If you need 300 sends a day and a healthy mailbox tops out near 50, the answer is six warmed mailboxes rotating sends, not one mailbox pushed six times past its safe ceiling. Each mailbox stays under its own limit; the campaign hits its target volume; no single inbox looks anomalous to the provider.
If you run three mailboxes on the same domain each sending 60 cold emails a day, Gmail sees 180 emails a day from that domain, not 60 — keep the domain total under roughly three times what a single warmed mailbox handles comfortably. Gmail is primarily reputation-signal-driven; Outlook is more IP-reputation-driven and tolerates moderate steady volume better than it tolerates spikes.
After any break longer than two weeks, treat the mailbox like a recently warmed one and start at 50% of your previous volume.
A free Outlook.com or Gmail account, or a paid mailbox that sat unused for months, has no recent sending history, so providers treat it as new. Start at 5 to 10 a day and ramp from there. If you have been away more than two weeks, restart at half your previous volume. Free consumer accounts are also the easiest to restrict, so move cold outreach to a custom domain on Google Workspace or Microsoft 365.
Volume limits apply per mailbox, but reputation attaches to the domain. A spike on your main domain puts your normal customer email at risk too. Run cold outreach from separate domains that look like yours, keep each domain's total daily volume modest, and warm every mailbox before the first campaign send.
A mailbox with real sending history — genuine opens, replies, and time spent in the inbox before cold outreach starts — tolerates meaningfully higher volume than an identical mailbox with none. Warmup is what raises the ceiling described above, not a workaround for ignoring it.
It depends entirely on the mailbox's age and warmup status, not a fixed number. A brand-new mailbox should start around 5–10 a day; a warmed, established one can typically handle 40–50. Provider technical limits are much higher than either figure — reputation-based filtering throttles you long before you hit the platform's actual cap.
Match the pace to your mailbox's warmup status, not the size of the list. Sending a large new list all at once from a cold mailbox is the fastest way to trigger spam filtering — spread it across warmed mailboxes and a ramping schedule instead.
Open and reply rates drop, bounce rate climbs, and providers start routing your mail to spam or throttling delivery silently — often with no bounce or error to alert you. Repeated overuse can get a domain flagged for an extended period. Backing off volume and resuming a slower ramp usually recovers it.
Several. Once your target volume exceeds a single warmed mailbox's safe ceiling (commonly 40–50 a day), add more warmed mailboxes and rotate sends across them rather than pushing one mailbox past its limit.
Roughly 20% more per week, not per day. Watch Postmaster reputation and seed placement at each step — if either degrades, pause and hold at the current level before continuing.
Google Workspace allows 2,000 messages a day per user, Microsoft 365 allows 10,000 recipients a day per mailbox, Zoho meters 50 to 500 external emails an hour, Hostinger Titan runs from 300 to 1,000 a day by plan, and GoDaddy Workspace Email allows 500 recipients a day. These are technical caps. The safe cold email number is 40 to 50 a day per warmed mailbox on any of them.
You can, but it is the riskiest option. Outlook.com allows roughly 300 recipients a day at most, starts new accounts lower, and can restrict an account that sends in bulk. Use a custom domain on a business mailbox and warm it first.
Do not cold email from your primary domain at all. Reputation attaches to the domain, so a spike hurts your normal email too. Use separate sending domains, and keep each domain's combined daily total to roughly three times what one warmed mailbox sends comfortably.
No. A mailbox with no recent activity has no sending history, so providers treat it like a new one. Start at 5 to 10 a day, or at half your old volume after a break of more than two weeks, and ramp over several weeks while warmup builds real engagement.
Keep it under about 2%. Above that, providers read the sender as careless with list quality, and placement drops. Verify addresses before sending and remove hard bounces immediately.
Run a free deliverability check on your sending domain — SPF, DKIM, DMARC, and spam-trap risk — before you send another outreach sequence.
Summarize with AI
Warmerly warms every mailbox you send from and paces your volume automatically, so you can add sending capacity instead of pushing one inbox past a safe limit. Start free.
