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About this tool
Predict how likely your email is to reach the inbox with a rule-based content audit — spam signals, subject quality, link safety, HTML structure and best practices, scored entirely in your browser.
Email Deliverability Predictor audits a subject line, sender address and message body against a fixed set of content rules — spam-trigger phrases, stacked urgency, shouting caps, repeated punctuation, insecure or shortened links, missing unsubscribe and postal address, HTML that email clients cannot render — and scores five weighted categories: content 30%, subject 20%, HTML structure 20%, links 15% and best practices 15%. Each finding carries a penalty of 20 points for an error, 10 for a warning and 4 for an info note, producing an overall score, a spam-risk figure and an inbox-probability estimate deliberately capped at 97%. It is for marketers and developers who want to fix the content half of deliverability before hitting send; it cannot see sender reputation or your SPF, DKIM and DMARC setup.
Open Email Deliverability Predictor on AltFTool — it loads instantly in your browser.
Paste your subject line and email content (plain text or HTML source).
Optionally add the sender address for extra checks like no-reply and free-domain warnings.
Click Analyze — or turn on auto-analyze to re-score as you edit.
Work through the issues and recommendations, then copy or download the report.
There is no black-box score: each issue names the rule, the severity, why it matters and the exact fix, and the penalties are fixed at 20 / 10 / 4 by severity.
Spam and urgency phrases are marked in the rendered copy with suggested alternatives, so you edit the sentence rather than hunt for the word.
In plain-text mode the HTML structure category is dropped and its 20% weight redistributed, so a text email is not punished for lacking markup it should not have.
Aim for 30 to 50 characters — long enough to carry the value proposition, short enough to avoid truncation in most inbox previews. Subjects outside that band are flagged as an info note here, and anything over 70 characters is raised to a warning.
No, and it caps its own inbox-probability estimate at 97% for that reason. Actual placement also depends on sender reputation, list hygiene, engagement history and SPF/DKIM/DMARC authentication — none of which are visible from the message content alone.
The strongest content signals it checks are stacked urgency and spam-trigger phrasing, excessive capitalisation, repeated punctuation like '!!!', URL shorteners, non-HTTPS links, more than 10 links in one message, and image-heavy emails with almost no text. Each of these is marked as a spam signal and feeds a separate spam-risk figure alongside the quality score.
85 and above reads as Excellent, 70–84 Good, 50–69 Moderate, 30–49 Risky and below 30 Likely Spam. The band is calculated from 70% of the structural quality score plus 30% of the inverse spam risk, so an email cannot earn a comfortable label on tidy formatting while stacking spam signals.