What is email deliverability and how do you improve it?
Email deliverability sounds technical, but it is a simple question: do your emails land in the inbox or do they vanish into spam folders and bounce queues?
For small businesses relying on email marketing to nurture leads and retain customers, the answer matters a lot. If only 75% of your emails reach the inbox, one in four recipients never sees them. This guide explains what affects deliverability and what you can fix today.
What is email deliverability?
Email deliverability is the percentage of emails that successfully reach your recipient's inbox, as opposed to being blocked, bounced or filtered as spam. It is different from delivery, which simply means the email was accepted by the receiving server. A delivered email can still land in the spam folder and never be seen.
Good deliverability means your messages land where people actually look. Poor deliverability means your carefully written email is invisible.
What causes poor email deliverability?
Several factors tell email providers like Gmail and Outlook to treat your email as suspicious:
- Sending from an unauthenticated domain. Without SPF, DKIM and DMARC records, providers cannot verify you are who you claim to be, and they treat your email with suspicion.
- A poor sender reputation. If recipients mark your emails as spam or rarely open them, providers flag your domain and future sends are more likely to be blocked.
- Buying email lists. Sending to people who never signed up guarantees spam complaints and damages your reputation fast.
- Spammy content. Words like 'free', 'guaranteed' and all-caps headlines trigger filters, but the biggest trigger is misleading subject lines that promise one thing and deliver another.
- Low engagement. If most of your list has not opened an email in six months, providers see you as irrelevant and start blocking your sends.
- Bounce rates. Sending to invalid or outdated addresses hurts your reputation every time.
Six ways to improve your email deliverability
1. Authenticate your sending domain. Set up SPF, DKIM and DMARC DNS records. Most email platforms (Mailchimp, Campaign Monitor, Brevo) provide setup guides. This is the single most important step.
2. Only send to people who opted in. A double opt-in (where subscribers confirm their email) gives you a clean, engaged list. Never buy a list - it destroys deliverability in days.
3. Clean your list regularly. Remove subscribers who have not opened in 90-180 days. A smaller, engaged list performs far better than a large, cold one.
4. Warm up a new sending domain. If you send from a new domain, start with small volumes (50-100 per day) and increase gradually over 2-4 weeks. Rapid volume spikes look like spammer behaviour.
5. Monitor your deliverability. Free tools like Google Postmaster Tools and MXToolbox show your sender reputation and any blacklisting. Paid email platforms include deliverability dashboards.
6. Write honest subject lines. If your subject promises a discount, the email must deliver it. Misleading subject lines are the fastest route to spam folders, even if the content is good.
Does email deliverability affect marketing ROI?
Directly. If 25% of your emails never reach the inbox, your open rates, click rates and conversion numbers are all based on a fraction of the audience you think you are reaching. Improving deliverability from 75% to 95% can more than double the effective reach of every campaign you send.
Victory Digital helps small businesses build marketing systems that actually work - from content marketing and email strategy to the technical foundations like deliverability. See how our content marketing and email strategy services can help at https://victory.digital/content-marketing, or start with a free SEO report at https://victory.digital/run-a-seo-report.
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