How many cold emails can you send per day per mailbox?
Updated 17 October 2026 · 6 min read
Short answer
For cold outreach, send about 30 emails per mailbox per day and no more than about 50, counting follow-ups. Provider hard limits are much higher (Google Workspace allows 2,000 messages per user per day, or 500 on trial accounts; Exchange Online allows 10,000 recipients per day), but those are for normal business mail, and cold email sent near them gets filtered. To send more, add mailboxes and domains instead of raising the per-mailbox number.
Two kinds of limit
There is the hard limit a provider enforces (exceed it and sending is blocked for up to 24 hours) and the practical limit where cold email keeps landing in the inbox. For cold outreach, the practical limit is much lower and is the one that matters.
Provider hard limits
| Provider | Limit | Notes |
|---|---|---|
| Google Workspace (paid) | 2,000 messages per user per day | Also 3,000 external recipients/day and 500 external recipients per message |
| Google Workspace (trial) | 500 messages per user per day | Rises after the account has paid at least $100 (can take up to 75 days) |
| Microsoft 365 / Exchange Online | 10,000 recipients per day | Also 30 messages per minute and up to 1,000 recipients per message |
Practical limits for cold email
| Mailbox state | Cold emails per mailbox per day |
|---|---|
| Days 1–21 (warming up) | 0; warmup only, ramping from ~2 to ~30 |
| Weeks 4–5 | 10–20, rising gradually |
| Established, healthy metrics | ~30 (conservative), up to ~50 |
| Bounces or spam placement rising | Cut back or pause and let warmup run |
These are practitioner guidelines, not numbers published by Google or Microsoft. They are conservative because reputation is judged on complaints, bounces and engagement, and cold email naturally gets fewer replies and more ignored messages than normal business mail. Follow-ups count toward the daily total.
How to scale volume safely
- 1
Set the target
Decide your total daily sends, including follow-ups.
- 2
Divide by 30 for mailboxes
1,000 emails a day needs about 34 mailboxes; 300 a day needs 10.
- 3
Spread 2–3 mailboxes per domain
34 mailboxes is about 12–17 domains. See how many mailboxes per domain.
- 4
Warm up before sending
Allow about three weeks per new mailbox. See how to warm up a new domain.
- 5
Configure the sequencer
Set a daily cap per mailbox, random gaps between sends, and rotation across all mailboxes in the campaign.
- 6
Add capacity before you need it
Warm new domains while current ones are working, so you can rotate without dropping volume.
Volume vs mailboxes
| Daily emails | Mailboxes (30/day) | Domains (3 per domain) |
|---|---|---|
| 150 | 5 | 2 |
| 300 | 10 | 4 |
| 1,000 | 34 | 12 |
| 3,000 | 100 | 34 |
Signs you are sending too much
- Hard bounce rate above about 3% of sends.
- Gmail spam rate in Postmaster Tools approaching 0.3% (Google's stated limit; it recommends under 0.1%).
- Warmup emails starting to land in spam.
- Reply rates falling sharply with no change in copy or list.
- Sending errors or temporary suspension messages from the provider.
Mailbox count is the main cost lever. With ReplyDak, mailboxes start at $2.69 each (Starter $35/month for 10, Growth $87 for 30, Scale $269 for 100), with warmup and DNS setup included. Estimate yours with the cost calculator or see pricing.
Need more daily volume? Add mailboxes in ReplyDak and they are spread across domains, authenticated and warmed automatically.
Domains, DNS, Google Workspace mailboxes and warmup. From $2.69 per mailbox ($35 for 10).
FAQ
How many cold emails can I send per day from one Gmail / Google Workspace account?
Google's hard limit is 2,000 messages per user per day (500 on trial accounts), but for cold outreach keep each mailbox to about 30 a day and under 50.
What is the Microsoft 365 daily sending limit?
Exchange Online allows 10,000 recipients per day and 30 messages per minute per mailbox. For cold email, the same 30–50 a day guideline applies.
How do I send 1,000 cold emails a day?
Use about 34 warmed mailboxes at 30 a day each, spread across 12–17 domains, with SPF, DKIM and DMARC on every domain.
What happens if I exceed Google's sending limit?
Google can temporarily block the user from sending, typically for up to 24 hours. Repeated cold sending at high volume can also lead to account suspension.