Email Spam & Subject Line Checker
Free email spam checker and subject line tester. Score spam risk, preview the inbox in Gmail and Outlook, and get concrete fixes. Nothing is sent.
Paste your subject line and email body below. The checker scores spam risk, shows how the email looks in the inbox, and lists the exact changes to make. Nothing is sent and nothing is stored, it all runs in your browser.
Your email
Start composing above to see your spam score, inbox preview and a prioritized fix list.
Suggested subject
What we found
This is a heuristic on the signals inside your message. It cannot see your domain reputation or your SPF, DKIM and DMARC setup, so treat it as an indicative pre-send check, not a guarantee of inbox placement.
Why your emails land in spam
Most emails are not blocked for one dramatic reason. They get filtered for a pile of small signals: the words you use, how the message is formatted, and whether your sending domain is trusted. The checker above scores the first two, the signals inside your message. Here is the full picture.
Content and wording. Filters still weigh the words in your subject and body. A single "free" will not sink you, but a cluster of trigger words like guaranteed, act now or risk-free raises your score fast.
Formatting. ALL-CAPS, walls of exclamation marks, three emojis in the subject, and a body stuffed with links all read as bulk mail. Keep it to one link and normal sentence case.
Sender reputation and authentication. The biggest factor is one no content tool can see: your domain reputation and whether SPF, DKIM and DMARC are set up. Sending cold from a gmail.com address is filtered far more aggressively than a properly authenticated company domain.
Engagement and list hygiene. Mailbox providers watch how people react. Low open rates, spam complaints and dead addresses teach Gmail to route you to spam. Clean your list and warm up new domains before you scale.
How long should a subject line be
Thirty to fifty characters is the sweet spot. Gmail shows about seventy characters on desktop and roughly forty on mobile, Outlook a little less, so put the words that matter first. The inbox preview above shows exactly where your subject gets cut on each client.
Deliverability for sales teams
If you run outbound, a clean subject only gets you to the inbox. The next problem is keeping every reply, on both email and LinkedIn, attached to the right contact in your CRM. Hublead syncs your LinkedIn and email conversations straight into HubSpot so nothing slips between tools. It does not send emails for you, it makes sure the ones you send stay tracked where your pipeline lives.
Frequently asked questions
Why are my emails going to spam?
Usually a combination, not a single cause: spam trigger words, heavy formatting such as caps, exclamation marks and many links, a weak or unauthenticated sending domain, and low engagement on past sends. Fix the message signals with the checker first, then make sure SPF, DKIM and DMARC are set up on your domain.
What is a good email spam score?
Aim for 80 or above on this checker. Below 55, most filters will treat the message as promotional or spam. The score is relative guidance built from common filter signals, not an absolute verdict from any single mailbox provider.
How long should an email subject line be?
30 to 50 characters is the sweet spot. Gmail shows about 70 characters on desktop and roughly 40 on mobile, Outlook a little less, so put the words that matter first.
Is this an email deliverability test?
It tests the content you control: subject, copy, formatting, sender name and address. A full deliverability test also inspects SPF, DKIM, DMARC and your domain reputation, which depend on your sending setup rather than the message itself.
Do you send or store my email?
No. Everything runs in your browser. Nothing is sent, saved, or logged, so you can paste real copy safely.
