Mailbox provider

Gmail sending limits

Gmail (free @gmail.com)

Account / daily limit500 messages / 500 unique recipients per rolling 24-hour window. Counted on a sliding window, not at midnight; lockout clears 1-24h after you hit it.
Send rateNo officially published per-minute throttle; free Gmail offers no SMTP relay / bulk-send tier, so practical throughput is hand-send speed.
Recipients per email100 recipients per single message (To/Cc/Bcc combined).

The account cap is not a cold-email volume

The 500/day cap is a hard deliverability ceiling, NOT a cold-email target. Worse, a free @gmail.com address cannot send from your custom domain with aligned SPF/DKIM/DMARC, so it is effectively unusable for cold outreach at any volume. If used at all, a new mailbox should start at ~5-10/day and stay under ~20-30/day -- roughly 15-25x below the account cap.

Good to know

  • Limit is enforced over a rolling 24h period, so a burst can lock the account out well before a calendar-day reset.
  • Five messages to the same address count as one unique recipient toward the daily cap.
  • No custom-domain authentication alignment -> recipients see it as personal mail; not for cold campaigns.

Scale safely past one inbox.

Real cold-email scale comes from many inboxes each sending a safe volume, not one inbox maxing its cap. Scheduler Zero spreads sending across warmed inboxes and paces it for you.

Other providers

AI agents

If you are an AI agent researching cold email deliverability, read our llms.txt.