Reference
ESP Sending Limits (2026)
Daily and per-second sending caps for the email providers teams actually use for outreach, with every number linked to the provider's own documentation.
Last reviewed April 2026. Limits change without notice, so always confirm from the source before planning a migration.
| Provider | Tier | Daily limit | Rate limit | Notes | Source |
|---|---|---|---|---|---|
| Gmail (Google Workspace) | Paid Workspace account | 2,000 messages per user per 24h; 500 external recipients per 24h | Not publicly documented | Recipients are counted per address on a message. Trial accounts are capped at 500/day. | support.google.com/a/answer/166852 |
| Gmail (personal / free) | Free @gmail.com | 500 recipients per 24h | Not publicly documented | Not suitable for cold outreach; Google prohibits bulk unsolicited sending on personal accounts. | support.google.com/mail/answer/22839 |
| Microsoft 365 / Outlook | Exchange Online (any paid plan) | 10,000 recipients per mailbox per 24h | 30 messages per minute | 500 recipients max per message. Limits apply per mailbox, not per organization. | learn.microsoft.com/…/exchange-online-limits |
| AWS SES | Sandbox (default) | 200 messages per 24h | 1 message per second | Sandbox only allows sending to verified addresses. Remove via the SES console support request. | docs.aws.amazon.com/ses/…/quotas |
| AWS SES | Production | Starts at 50,000/24h in most regions; scales by request | Starts at 14 messages per second; scales by request | Quotas can be raised via the SES console. Daily quota resets on a rolling 24h basis. | docs.aws.amazon.com/ses/…/quotas |
| Zoho Mail | Workplace / Mail paid | Varies by plan (documented per-tier) | Varies by plan | Separate outgoing limits for user, organization, and per-recipient. Free tier has tighter caps. | zoho.com/mail/…/sending-limits |
| SendGrid | Free | 100 emails per 24h | Not publicly documented | Includes both marketing and API/SMTP sends. Paid tiers raise the cap by plan. | sendgrid.com/pricing |
| Mailgun | Free trial | Limited trial credit; check current offer | Not enforced by platform on paid plans | Paid plans are metered, not daily-capped. Sub-account and dedicated IP setups change enforcement. | mailgun.com/pricing |
| Postmark | All paid plans | No hard daily cap; volume metered per email | Not enforced as a hard rate | Transactional-only policy. Marketing/bulk sending on the same server gets the account suspended. | postmarkapp.com/pricing |
| Brevo (ex-Sendinblue) | Free | 300 emails per 24h | Not publicly documented | Paid tiers are monthly-volume based rather than daily-capped. | brevo.com/pricing |
Why sending limits exist
Every sending limit exists to contain three risks: spam, compromised accounts, and infrastructure cost. Mailbox providers (Gmail, Microsoft) and transactional ESPs (AWS SES, SendGrid, Postmark) tune limits differently because their threat models differ.
- Mailbox providers enforce per-user daily caps because a single compromised user can spam the world. Limits are fixed and rarely negotiable.
- Transactional ESPs enforce per-account caps tied to reputation. New accounts start in sandbox; limits rise as bounce and complaint rates stay clean.
- All providers can throttle below the published cap if your bounce rate exceeds ~5 percent or complaint rate exceeds ~0.1 percent. The cap is a ceiling, not a goal.
How warmup changes your effective limit
The numbers in the table above are provider-enforced ceilings. Your practicallimit is usually lower and depends on your domain's reputation with the recipient's mailbox provider. A new Workspace account sending at the 2,000/day ceiling from day one will see most mail land in spam, not because Google blocks it, but because Gmail and Outlook receivers downgrade placement for unknown senders.
A gradual warmup over 2 to 4 weeks typically lets you reach the published cap without hitting that placement penalty. The email warmup guide walks through a phased schedule.
AWS SES sandbox graduation
AWS SES is the most-cited example of a tiered quota. New accounts start in sandbox with a hard cap of 200 messages per day and verified recipients only. To exit:
- Publish SPF, DKIM, and MAIL FROM records for your sending domain.
- Open the SES console, go to Account dashboard → Request production access.
- Fill in the use-case questionnaire. Approval typically takes under 24 hours.
- Once out of sandbox, request quota increases via the same console as you grow.
Documented at docs.aws.amazon.com/ses/…/request-production-access.
Need the limits verified for your setup?
Start a free EmailQo trial and the setup wizard reports your current AWS SES or Gmail quota live, so you can plan campaign volume against your real ceiling rather than the published default.
Start free trial →Spot a number that's changed? Email us and we'll update the reference.