"Daily user sending limit exceeded" means Gmail has paused your outgoing mail, usually for up to 24 hours. You can still read and receive. The fix is to wait, then send less per day when you restart. Opening a second account to push the same list through is the move that turns a one-day pause into a flagged account.
Gus found this out on a Tuesday. He runs a service company that maintains commercial coffee machines for offices, and he loaded 640 addresses into a mail merge on a free Gmail account at 8 a.m. About 500 went out. The other 140 came back with an error and he assumed a glitch. By lunch he couldn't send anything. Below is how to read the message you got, what to do while you wait, and the daily cap that keeps it from happening again.
What the error says, in its two forms
You will see one of two messages, depending on where you send from. In the Gmail window it reads "You have reached a limit for sending mail." In a bounce from a tool, an add-on or an SMTP connection it shows up as "550 5.4.5 Daily user sending limit exceeded." Both mean the same thing: the account hit its quota. Google's published SMTP error list gives that exact wording for 5.4.5.
A different error looks similar and isn't. The code 421 4.7.28 says Gmail "has detected an unusual rate" of mail, which is about your pattern and your reputation, not a counted quota. If that's what you have, slowing down helps, but you also need to check authentication. Your message has been blocked in Gmail: causes and fixes covers those.
How long the pause lasts
Google's help page for personal accounts says you should be able to send again within 1 to 24 hours. Its Workspace page says users can't send new messages for up to 24 hours, while still having access to their inbox and other Google services. Google doesn't publish an exact reset clock, so plan on the full 24 hours from the moment you were blocked, and treat anything sooner as a bonus.
Match your situation to the cause
| What happened | Likely cause | What to do |
|---|---|---|
| Free Gmail, you sent hundreds in one burst | You passed 500 emails in a day | Wait. Restart at a fraction of that |
| Free Gmail, well under 500 sends | Recipients counted, not messages: To, CC and BCC all count. Or an add-on sent more than you saw | Count recipients in Sent. Check which tools can send as you |
| Workspace, under 2,000 sends | A lower cap applied: 1,500 for mail merge, 500 on a trial account, 3,000 external recipients | Check which cap you hit, wait, then pace |
| Error on the first day of a new account | New accounts get closer scrutiny | Send a handful a day for a week |
| You didn't send anything unusual | Someone else may be sending as you | Open Sent and Google's security check-up today |
The numbers in the table are Google's published limits for personal accounts and for Workspace as I read them in October 2026. They're ceilings. The Gmail versus Workspace comparison sets them side by side.
Free Gmail versus Workspace, in plain terms
Free Gmail allows roughly a quarter of what Workspace does: 500 a day against 2,000 per Google's published pages. That sounds like a reason to upgrade, but it rarely is one. A sender who stays at 50 a day is nowhere near either ceiling. Upgrade for the custom address and control of your authentication records, not for headroom you shouldn't use. If you're weighing it anyway, see the comparison linked above.
Three look-alikes that are not this error
A message that bounced with "Address not found" is a bad address, and has nothing to do with quota. A message that says it was "blocked" is a reputation or authentication problem. A message sitting in your Outbox with no error at all is usually a connection or attachment problem. Only the wording about a limit, or the 5.4.5 code, is this one. Mixing them up sends you to the wrong fix.
What to do while you're paused
Ten minutes of work saves you a mess tomorrow:
- Find out who got an email and who didn't. Open Sent and the bounce messages. If you use a sheet, mark the 140 unsent rows now.
- Cancel any scheduled sends or active sequences so nothing queues up behind the pause and fires all at once.
- Don't open a second account to keep going. A fresh account sending a batch looks worse than a paused old one.
- Don't resend from a different tool the same hour. The message is the same and so is the pattern.
- Use the time to clean the unsent rows. Remove duplicates and anyone who already replied.
Why bursts trigger it
Quotas count everything leaving the account in a window: first emails, follow-ups, replies you send by hand, and test messages. A common surprise is the total. Thirty new emails, thirty follow-ups, and ten replies is 70 in a day, and a second campaign running from the same inbox doubles part of it. Gus's problem was a single burst of 640, which is more than Google allows even before reputation comes into it.
A daily cap that keeps you well under
Set one number for the whole inbox and make every tool respect it: new emails plus follow-ups plus the replies you expect to send. Start at 20 to 50 a day and raise it a little each week, as laid out in how many cold emails per day from Gmail. A split that works for a mature inbox is 30 new, 15 follow-ups and 5 replies, which is 50. Google's limits are far higher, but your reputation is built at the small number, not the big one.
Restart without a spike
Day two, send about half of your usual volume, spread across the morning and afternoon. For Gus's 140 leftover rows that's 40 a day for three and a half days, plus his normal follow-ups, not 140 on Wednesday. Watch the first day's bounces: if more than two or three appear, stop and read the codes, because an error that returns after you were under the cap points at reputation rather than quota. The longer treatment of building up is in warming up a Gmail account, and the basics of who judges your mail are in cold email deliverability basics. If nothing is going out at all and there's no error, emails not sending from Gmail is the checklist to run.
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