As of October 2026: Google Workspace allows 2,000 messages a day per user (500 on trial accounts). Exchange Online (Microsoft 365) allows 10,000 recipients a day per mailbox and 30 messages a minute, plus a tenant-wide cap on external recipients. Those are ceilings for normal business mail, not cold email targets. Cold email providers publish their own guidance: Winnr recommends 10 to 20 cold emails per mailbox per day and 50 or fewer including warming, Maildoso caps mailboxes at 15 a day, and Mailforge recommends 30.
Every provider has two kinds of limit. There is the hard limit it enforces, after which mail stops sending. Then there is the practical limit for cold email, which is far lower, because the receiving providers, not your own, decide whether cold mail reaches the inbox. This page lists both, with sources, as of October 2026.
The comparison table
| Provider | Hard limit per mailbox | Practical cold volume | Price per mailbox | Setup |
|---|---|---|---|---|
| Google Workspace | 2,000 messages/day (500 on trial); 10,000 total recipients/day; 3,000 external recipients/day | Google publishes no cold email figure; senders typically stay far below the limit | $7/user/month on Business Starter annual, $8.40 flexible | One user per mailbox; you publish SPF, DKIM, DMARC yourself |
| Microsoft 365 (Exchange Online) | 10,000 recipients/day; 30 messages/minute; tenant-wide external recipient cap | Microsoft directs bulk commercial email to third-party providers | $4/user/month on Exchange Online Plan 1 (annual); $7 on Business Basic | One user per mailbox; you publish the DNS records |
| Winnr | You set the daily limit per mailbox in your sending tool | 10 to 20 cold/day (15 default), 50 or fewer including warming | $69/month for 50 ($1.38 each), $189 for 200; extra mailboxes $1 | Automatic SPF, DKIM, DMARC; mailboxes created in bulk |
| Maildoso | Up to 15 emails/day per mailbox on every plan | Same as the cap | From $0.49 at 1,000 mailboxes | Automatic |
| Mailforge | 100/day maximum per mailbox (its stated guidance) | 30/day recommended, 2 to 3 mailboxes per domain | See Mailforge's pricing page | Automatic |
Competitor figures are from each provider's own pricing page as of October 2026; links are in the sources. For a full price comparison see Winnr vs Maildoso and Winnr vs Mailforge.
Google Workspace
The hard numbers
From Google's Gmail sending limits in Google Workspace, checked October 2026:
- 2,000 messages per day per user (1,500 for mail merge), and 500 per day on trial accounts.
- 10,000 total recipients per day, of which 3,000 external.
- 3,000 unique recipients per day, of which 2,000 external.
- 2,000 recipients per message (at most 500 external), and 100 per message for users sending through SMTP from a mail client or sending tool.
Every message the account sends counts, including warmup emails sent by a warmup tool. Once you hit a limit, the account can't send until the rolling 24-hour window clears.
What it costs
Business Starter is $7 per user per month on an annual plan and $8.40 on the flexible plan, as of October 2026. Each sending mailbox is a user, so 50 mailboxes cost $350 to $420 a month before any sending tool.
Suspension risk
Google Workspace is built for everyday business email, and accounts that look like bulk cold senders can be suspended. If that happens, see what to do when Google Workspace suspends you. For how Winnr mailboxes compare, see the Google Workspace alternative for cold email.
Microsoft 365 (Exchange Online)
The hard numbers
From Microsoft's Exchange Online limits (page updated September 2026), the same on Business Basic, Standard, Premium and Enterprise plans:
- Recipient rate limit: 10,000 recipients per day per mailbox (rolling 24 hours).
- Message rate limit: 30 messages per minute. Excess submissions are throttled into the following minutes.
- Recipients per message: customizable up to 1,000.
- Tenant External Recipient Rate Limit (TERRL): a cap on external recipients for the whole tenant per day, which depends on how many licenses the tenant has. Trial tenants are capped at 5,000 external recipients a day.
- onmicrosoft.com domains: mail sent from the default onmicrosoft.com domain is limited to 100 external recipients per organization per day.
Microsoft's own documentation says Exchange Online customers who need to send legitimate bulk commercial email should use third-party providers that specialize in it.
Authentication changes
Microsoft has postponed retiring Basic Auth for SMTP AUTH: it keeps working until the end of December 2026, when it becomes disabled by default for existing tenants. Admins can turn it back on, but plan for sending tools that connect over SMTP with a password to need OAuth after that. The details and dates are in Microsoft 365 for cold email in 2026.
What it costs
Exchange Online Plan 1 is $4 per user per month with an annual commitment, and Microsoft 365 Business Basic is $7 since Microsoft's July 1, 2026 price update.
Receiving-side rules: Gmail, Yahoo, Outlook.com
The limits that matter most for cold email are set by the providers your prospects use. None of them publish a "safe" cold volume, but they do publish requirements:
| Receiver | Applies to | Key requirements |
|---|---|---|
| Gmail (sender guidelines) | All senders; extra rules at 5,000+ messages a day to personal Gmail accounts | SPF or DKIM for all; SPF, DKIM and aligned DMARC for bulk; spam rate under 0.3%, and Google says to aim under 0.1% |
| Yahoo (sender best practices) | All senders; extra rules for bulk senders | SPF or DKIM for all; SPF, DKIM and DMARC for bulk; spam rate under 0.3%; honor unsubscribes within 2 days |
| Outlook.com (high-volume requirements) | Domains sending 5,000+ messages a day to Outlook.com consumer addresses, since May 5, 2025 | SPF and DKIM pass, DMARC at least p=none and aligned; non-compliant mail is rejected with 550 5.7.515 |
Staying under 5,000 a day per domain doesn't exempt you from filtering. It only means the stricter published rules don't apply to you. Meet them anyway.
Cold email SMTP providers
Cold email infrastructure providers sell mailboxes on their own sending infrastructure, priced for many mailboxes rather than per seat, with authentication set up automatically. Most publish a per-mailbox volume, either as a hard cap or as guidance:
- Winnr: 10 to 20 cold emails per mailbox per day (15 by default) and 50 or fewer in total including warming. You set the limit in your sending tool. Startup is $69/month for 50 mailboxes (about 2,500 emails a day including warming), Enterprise $189 for 200 (about 10,000), and extra mailboxes are $1 a month each. Warming is built in at $0.60 per mailbox per month. See Winnr pricing.
- Maildoso: "Sending up to 15 emails per day" is listed on every plan on its pricing page, as of October 2026.
- Mailforge: its pricing page recommends 30 emails per mailbox per day (100 maximum) and 2 to 3 mailboxes per domain, as of October 2026.
These aren't the same as a Google or Microsoft limit. They reflect what each provider thinks keeps its infrastructure and your domains healthy. Lower per-mailbox volume means you need more mailboxes for the same total, which is why per-mailbox price matters so much at scale.
Transactional email APIs
Transactional email services are built for mail people asked for: receipts, password resets, notifications. They offer high throughput, but most of their acceptable-use policies prohibit unsolicited bulk email, and they watch bounce and complaint rates closely. Read the policy before using one for cold outreach; for most cold email programs they're the wrong tool.
How to size your infrastructure
- Mailboxes = daily cold email target ÷ 15 (the normal pace), rounded up. Use ÷ 10 to be cautious, ÷ 20 at most.
- Domains = mailboxes ÷ 5, rounded up.
Worked example: 1,000 cold emails a day
- 1,000 ÷ 15 = 67 mailboxes, on 67 ÷ 5 = 14 domains.
- Winnr: Startup ($69 for 50) plus 17 extra mailboxes at $1 = $86/month, plus one-time domain purchases (a .com is about $13).
- Google Workspace Business Starter: 67 × $7 = $469/month on an annual plan, or 67 × $8.40 = $562.80 flexible.
- Exchange Online Plan 1: 67 × $4 = $268/month on an annual commitment; 67 × $7 = $469 on Business Basic.
The cold email calculator runs this for any target, and how many domains you need covers the domain side.
Mixing providers
Some teams keep a few Google Workspace or Microsoft 365 inboxes for their highest-value prospects and run the bulk of their volume on SMTP mailboxes. That works as long as each mailbox follows the same per-mailbox volume guidance and every domain is authenticated. SMTP vs Google Workspace vs Microsoft 365 covers the trade-offs, and the Outlook alternative for cold email covers the Microsoft side.
Frequently Asked Questions
How many emails can Google Workspace send per day?
2,000 messages per day per user on paid accounts and 500 on trial accounts, with up to 10,000 total recipients and 3,000 external recipients a day, according to Google's sending limits page as of October 2026. Those are ceilings for normal business use, not cold email targets.
What is the Microsoft 365 sending limit?
Exchange Online allows 10,000 recipients per mailbox per day and 30 messages per minute, with up to 1,000 recipients per message, plus a tenant-wide limit on external recipients that depends on your license count. Trial tenants are capped at 5,000 external recipients a day.
Do warmup emails count toward the daily limit?
Yes. Every message an account sends counts, including warmup emails. On Winnr, keep each mailbox at 50 or fewer emails a day in total, with 10 to 20 of them cold.
What is the safest number of cold emails per mailbox per day?
Winnr recommends 10 to 20, with 15 as the default. Maildoso caps its mailboxes at 15 a day and Mailforge recommends 30, as of October 2026. Whatever the provider, scale by adding mailboxes rather than raising per-mailbox volume.
Which is cheaper for 1,000 cold emails a day?
At 15 cold emails per mailbox you need 67 mailboxes. That is $86 a month on Winnr (Startup plus 17 extra mailboxes), $469 a month on Google Workspace Business Starter with an annual plan, or $268 on Exchange Online Plan 1, before domains and sending tools.
Sources
All checked October 6 to 7, 2026.
- Google, Gmail sending limits in Google Workspace; Email sender guidelines; sender guidelines FAQ.
- Microsoft, Exchange Online limits; Outlook's requirements for high-volume senders.
- Yahoo, Sender best practices.
- maildoso.ai/pricing and mailforge.ai/pricing.
- Google Workspace and Microsoft 365 prices: the providers' US list prices as of October 2026.