February 18, 2026
Email Deliverability Score: What It Is and Why It Matters
Understand email deliverability scores. Learn what factors affect your score, how to check it before sending, and how to improve inbox placement rates.
What is a deliverability score?
A deliverability score is a number (typically 0-100) that predicts how likely your email is to reach the inbox instead of the spam folder. It analyzes your email content, sending infrastructure, and sender reputation.
Why check before sending?
Most email tools show you open rates and bounce rates after you've already sent. By then, the damage is done — your emails are in spam, your domain reputation is hurt, and your campaign is wasted.
Checking before sending lets you fix problems before they happen.
What affects your deliverability score
Content factors (what you write)
| Factor | Impact | What to do |
|---|---|---|
| Spam trigger words | High | Avoid "free", "guarantee", "click here" |
| Email length | Medium | Keep 50-150 words for cold email |
| Number of links | High | 0-1 links maximum |
| ALL CAPS words | Medium | Never use all caps |
| Exclamation marks | Low | Maximum 1, preferably 0 |
| Image-to-text ratio | Medium | Plain text is best for cold email |
| HTML complexity | Medium | Simple HTML or plain text only |
Infrastructure factors (how you send)
| Factor | Impact | What to do |
|---|---|---|
| SPF authentication | Critical | Must pass |
| DKIM signing | Critical | Must pass |
| DMARC policy | High | Set up at minimum p=none |
| Sending domain age | High | Use domains aged 2+ weeks |
| IP reputation | High | Use reputable email providers |
| Sending volume | Medium | Stay below 50/mailbox/day |
Reputation factors (your history)
- Bounce rate (keep below 2%)
- Spam complaint rate (keep below 0.1%)
- Unsubscribe rate (healthy is below 1%)
- Engagement rate (replies improve reputation)
How HeraMail's deliverability score works
HeraMail calculates a 0-100 score on every email before you send it. The score checks:
- Spam word detection — Scans for 200+ known spam trigger words
- Length analysis — Flags emails that are too short or too long
- Link count — Warns if you have too many links
- Caps ratio — Detects excessive capitalization
- Overall readability — Checks that the email reads naturally
Score interpretation
| Score | Meaning | Action |
|---|---|---|
| 90-100 | Excellent | Send with confidence |
| 70-89 | Good | Review flagged issues |
| 50-69 | Risky | Fix issues before sending |
| 0-49 | Poor | Rewrite the email |
How to improve your score
Quick fixes - Remove spam trigger words - Shorten your email to under 150 words - Remove extra links (keep 0-1) - Remove ALL CAPS words - Simplify your HTML or use plain text
Long-term improvements - Build sender reputation gradually - Keep bounce rates low with list cleaning - Get replies (engagement signals help) - Use multiple mailboxes with rotation
Deliverability improvement checklist
- [ ] Check deliverability score before every send
- [ ] Fix all flagged issues before sending
- [ ] Maintain bounce rate below 2%
- [ ] Monitor spam complaint rate
- [ ] Clean email list monthly
- [ ] Test with mail-tester.com periodically
Check your deliverability score before sending — try HeraMail free: heramail.io