Cold Emails Going to Spam in Gmail? 10 Causes and Fixes
Cold emails going to spam in Gmail? Read Gmail's warning, find which of 10 causes is yours, and follow the fix order. Every rule checked on Google's pages.
Cold emails going to spam in Gmail usually come down to a handful of causes. Here are the 10 most common, how to spot each one and how to fix it.
The short answer: Cold emails usually land in Gmail spam for one of five reasons: SPF, DKIM or DMARC fail; the inbox wasn't warmed up; you send too much too fast; people mark you as spam; or your list bounces. Read Gmail's warning on the spam message first, fix authentication, then slow down, clean the list and ramp back up.
Step 1: read why Gmail flagged it
Gmail often tells you why it filtered a message. Send a test to a Gmail address you own, open it in Spam, and read the warning at the top. Then match it to a cause.
Gmail's warning (Google's wording) | What it usually means | Go to |
|---|---|---|
"Gmail can't confirm who sent you the email" | SPF, DKIM or DMARC isn't passing | Cause 1 |
"The email address looks very similar to the email address of a known sender" | Your domain looks like another brand's | Cause 10 |
"spammers often send emails with no content in the body or subject" | Empty subject or body | Cause 8 |
"their emails go directly to Spam" after an unsubscribe | You emailed someone who opted out | Cause 5 |
No warning | Reputation or recipient behaviour: volume, complaints, bounces or content | Causes 2 to 9 |
Warnings quoted from Gmail Help.
Then check "Show original"
In the message, open the three-dot menu and choose Show original. Look for SPF, DKIM and DMARC. Each should say PASS. Any FAIL is the first thing to fix.
Gmail's sender rules
Since 1 February 2024, everyone sending to Gmail accounts must meet a baseline, and senders of more than 5,000 messages a day to Gmail accounts must meet more (Google, email sender guidelines).
Rule | All senders | More than 5,000 a day to Gmail |
|---|---|---|
Authentication | SPF or DKIM | SPF, DKIM and DMARC |
From domain aligned with SPF or DKIM | Not required | Required |
Spam rate in Postmaster Tools | Below 0.3% | Below 0.3% |
Google's spam rate guidance | Below 0.10%, never 0.30% or higher | Same |
One-click unsubscribe | Not required | Required for marketing and subscribed mail |
TLS connection | Required | Required |
Most cold emailers stay well under 5,000 a day, but we still recommend all three records and alignment on every sending domain. They take minutes to set up and cover you if your volume grows.
10 reasons cold emails go to spam in Gmail
1. SPF, DKIM or DMARC fail
How to tell: Show original says FAIL or NONE for any of the three, or Gmail shows "Gmail can't confirm who sent you the email".
Fix: add all three records on every sending domain, and sign DKIM with your own domain, not your provider's. See SPF, DKIM and DMARC explained and the DMARC record guide.
2. The inbox wasn't warmed up
How to tell: the domain or inbox is weeks old, and the problem started with your first campaign.
Fix: start with small, steady volume and raise it slowly. Our guidance is 3 to 4 weeks of warmup before cold sending. See what is email warmup.
3. Too many emails per inbox
How to tell: each inbox sends hundreds a day, even though Google Workspace allows 2,000 (Gmail sending limits).
Fix: keep each inbox to about 30 cold emails a day (our guidance) and add inboxes to grow. See secondary domains for cold email.
4. Volume jumps overnight
How to tell: spam placement started the day you went from 20 to 200 emails, or you send in bursts.
Fix: Google says "Increasing your sending volume too quickly can result in delivery issues" and suggests "a common daily increase of 25% to 100%". It also asks senders to send at a steady rate rather than in bursts (Google, Top 10 Gmail sender issues).
5. People mark you as spam
How to tell: Postmaster Tools shows a spam rate above 0.10%, or replies say "stop emailing me". At low volume Postmaster Tools may show no data at all, so watch replies too.
Fix: tighten targeting, give an easy opt-out line, and never email anyone who opted out. Google's target is a spam rate below 0.10%, about 1 report per 1,000 emails.
6. Your list bounces
How to tell: more than 2% of a campaign bounces (our guidance), or bounces say the address doesn't exist.
Fix: verify every list before sending and remove hard bounces after each campaign. Old, scraped or bought lists are the usual source, and they also carry spam traps. See email bounce rate and spam traps explained.
7. Links and tracking
How to tell: the first email has several links, a link shortener, or open and click tracking on a shared tracking domain.
Fix: use one link or none in the first email, no shorteners, and a custom tracking domain if you track at all.
8. Heavy HTML, images or attachments
How to tell: the email looks like a newsletter, has a large image or an attachment, or has an empty subject or body.
Fix: send plain text that looks like one person writing to another. No attachments in a first email, and always a real subject line.
9. The same email sent thousands of times
How to tell: every recipient gets word-for-word the same text.
Fix: personalise the first line and the reason you're writing, and vary the wording across the sequence.
10. Your domain has a poor reputation or looks like another brand
How to tell: the domain is on a blocklist, shares a sending IP or domain with other senders, or Gmail shows "The email address looks very similar to the email address of a known sender".
Fix: check blocklists and request removal, stop sharing domains with other senders, and pick names that are clearly yours. Google notes that using the same IP or domain for multiple senders "can result in a low domain or IP address reputation". See domain reputation explained and the blacklist removal guide.
Do spam words send cold emails to spam?
Rarely on their own. Gmail weighs your domain's reputation and how recipients react far more than single words. Google's own advice on content is narrow: don't use emojis or symbols to imitate graphics, and don't put "Re:" or "Fwd:" in a subject unless it's a real reply or forward (Top 10 Gmail sender issues). Rewriting copy seldom fixes a problem caused by authentication, volume or a bad list. See how points add up in our SpamAssassin score guide.
Find your cause in this order
Check the cheap, certain things first and the slow, fuzzy ones last.
Gmail's warning: does the spam message say why?
Authentication: do SPF, DKIM and DMARC all pass in Show original?
Blocklists: is the domain or sending IP listed?
Volume: did spam placement start after a jump in sending?
List: did bounces go above 2%?
Complaints: is Postmaster Tools above 0.10%, or are replies angry?
Content: links, images, attachments, identical text?
The fix, in order
Pause cold sending from the affected inboxes. Keep warmup running.
Fix authentication until SPF, DKIM and DMARC all show PASS.
Check blocklists and request removal if you're listed.
Clean the list: verify it and remove bounced and risky addresses.
Simplify the email: plain text, one link or none, no attachments, a real subject line.
Restart small: 10 to 20 cold emails a day per inbox (our guidance), sent at a steady rate.
Ramp up slowly: Google's suggested daily increase is 25% to 100%. If Gmail defers mail, it says to pause 15 minutes, send one test, and stay below the volume that triggered the deferral for 24 hours.
Monitor: watch Postmaster Tools for spam rate and test placement with a seed list. See email deliverability testing tools.
How long does it take to get out of Gmail spam?
Once the cause is fixed, placement usually recovers over 2 to 4 weeks of lower, cleaner sending (our experience, not a Google figure). Google notes that Gmail can take time to adjust how it classifies your mail after spam rates improve. A badly damaged sending domain can take longer, and it's often faster to rest it and warm a new one.
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Frequently asked questions
Why are my cold emails going to spam in Gmail? Usually failed SPF, DKIM or DMARC, no warmup, too many emails per inbox, spam reports, or a list that bounces. Read Gmail's warning on the spam message and check Show original first.
How do I stop my emails going to spam in Gmail? Set up all three authentication records, warm up new inboxes, send about 30 cold emails a day per inbox at a steady rate, verify your list, keep emails plain, and only email people the message is relevant to.
Does Gmail allow cold email? Gmail doesn't ban cold email, but it filters mail people don't want. Authenticated, relevant, low-volume email with an easy opt-out reaches the inbox.
What spam rate does Gmail allow? Google requires a spam rate below 0.3% in Postmaster Tools and advises staying below 0.10%, about 1 report per 1,000 emails.
Do I need DMARC if I send fewer than 5,000 emails a day? Google only requires it above 5,000 a day to Gmail accounts, but we recommend it on every sending domain. It's one DNS record.
Why does Postmaster Tools show no data? Google says dashboards may show no data when volume is low, to protect Gmail users' privacy. Many cold email domains are below that level, so use seed tests and replies as your signal.
Can one word send an email to spam? Rarely on its own. Reputation, authentication and how recipients react carry far more weight.
Key terms
Spam rate: the share of your emails that Gmail users report as spam, shown in Postmaster Tools.
Show original: Gmail's view of a message's raw headers, including SPF, DKIM and DMARC results.
Bulk sender: in Google's rules, anyone sending more than 5,000 messages a day to Gmail accounts.
Deferral: a temporary rejection, where Gmail asks the sending server to try again later.
Seed list: test addresses at each mailbox provider used to see where an email lands.
