How To Improve Email Deliverability for Your Business

Oleksandr Rohovnin
Content Marketer
15 minute read
Oleksandr Rohovnin
Content Marketer
15 minute read

With an incredible 13.3% CAGR, email marketing is one of the most profitable ways to captivate future customers – but only if your emails successfully hit the recipient’s inbox without being blocked by the ISP or banished to the spam folder.

Email deliverability is a big deal for any business using emails. A well-written copy isn’t enough – and never has been – what you really need is to get your emails delivered to the destination point so they get noticed and clicked on.

Source: GIPHY

Read on to learn how to improve email deliverability for your business and convert more subscribers.

Email Deliverability vs. Email Delivery

For aspiring marketers, you first need to understand email deliverability and email delivery, as these two underlying email metrics help gauge emails from different perspectives.

Here’s the difference between email delivery and email deliverability:

  ➥ Email delivery is the percentage of emails that have reached ANY FOLDER in the recipient’s mailbox, including the spam folder. On the other hand, email deliverability is the percentage of emails that have reached the recipient’s INBOX.

Your email deliverability rate can’t be higher than your email delivery rate. And if it is higher, there must be a mistake in data processing or calculations.

Comparison of email delivery vs. email deliverability across four major parameters: route, passing criteria, control, and meaning

Email Deliverability Benchmarks To Proceed From

With email marketers constantly improving their campaigns – around 67% of marketers claim their emails get more opens than the year before – it’s worth knowing the current industry benchmarks so you can understand when you need to improve email deliverability.

Here’s the average email deliverability across industries:

Statistics on the percentage of marketing emails landing in the inbox, spam folder, and lost by the industries of finance, health, entertainment, sport & fitness, electronics, job & career, home & garden, and the "other" category.

As you can see, the average global marketing email deliverability rate is around 85%, meaning that 85 out of 100 emails go to the inbox, while around 12% end up in the spam folder, and around 3% are not delivered.

Surprisingly, email deliverability doesn’t depend much on the industry, with all industries falling within the 81% to 86% inbox deliverability range. And there’s another exciting fact: the more frequently you send emails, the lower the bounce rate.

Here you go:

Statistics on how email bounce rate depends on mailing frequency if sending emails daily, weekly, monthly, and other frequencies

But then again, it doesn’t mean that the emailing frequency directly correlates with the inbox placement or bounce rate, but rather that frequent feedback allows for better campaign optimization.

Long story short, you should have at least 98% of your emails delivered to their mailbox and 95% placed in the inbox. Anything below likely indicates technical issues, a low sender reputation, poor email list hygiene, or other problems with your email campaigns.

How To Check Email Deliverability

Surprisingly enough, you cannot know your exact deliverability rate because the Internet Service Provider—the only entity with access to this data—doesn’t disclose it.

However, there are two ways to more or less accurately gauge your deliverability rate:

By Measuring Associated Metrics Knowing your email delivery rate, bounce rate, spam complaint rate, and other performance metrics allows you to make an educated guess about your email deliverability metrics.
By Using Automated Email Software Detailed reports with email software like E-Delivery contain exhaustive data, including deliverability insights, retrievable in a few clicks

How To Test Email Deliverability

Testing email deliverability is simple if you’re open to field experiments. You can even send emails to your own addresses – the so-called seed testing – to see where your emails land. For this, however, you must create a list of fake email addresses with the ISPs, email clients, and devices you want to test within this small email deliverability audit.

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Email Deliverability Monitoring: Where Your Emails Land

There are three possible destinations for your emails:

  • Inbox
  • Spam folder
  • Sent back to you if not delivered

Naturally, you want all your emails to hit the primary folder—the one the recipient sees by default—to get more engagement. For most delivered emails, this will hold true, but some emails may still land in different folders— Social, Promotions, or Updates—depending on the email provider and the user’s inbox settings.

Don’t worry about that unless this is the spam folder.

The spam folder, though, is the one-way destination you might want to avoid at all costs. Even though some emails may still be retrieved from the spam folder by the user, there’s not much hope in general, especially if this is the user who marked the email as spam in the first place.


How To Avoid Spam Filters To Increase Email Deliverability

The ISP won’t tell you how many of your emails are spammy, so you must refer to metrics like, for example, the spam complaint rate. On top of that, subscribers who mark your emails as spam must be immediately removed from the mailing list.

Last but not least, your emails can come back to you as a hard or soft bounce:

Comparison of soft and hard email bounces by four parameters or factors: possible reasons, email server actions, sender reputation impact, and the recommended action on the sender's side

A returned email can be a soft or hard bounce, with the latter being far more dangerous. Soft bounces don’t necessarily require any action on your side  – just try to resend the email in a few hours – while hard bounces must be instantly removed from the mailing list. In fact, a hard bounce usually means you are blocked by the recipient’s ISP because of your bad reputation, spam emails, authentication failures, or other reasons.

How To Increase Email Deliverability Across Campaigns

Email Sender’s Reputation

As soon as you’ve signed a contract with your ISP, they are constantly monitoring your sender reputation – on a scale from 0 to 100 – based on how well your emails perform once they hit the inbox: open rates, click-through rate, unsubscribe rates, and more.

Even though there’s no exact algorithm for evaluating your credibility – not to mention algorithms differ with every ISP – it’s obvious that senders with better engagement receive greater reputation scores. Numbers-wise, a good email sender’s reputation score is 90 or above.

Advice on how to improve your email sender's reputation by improving your email list hygiene, increasing engagement, fixing technical issues, and choosing a reputable ESP

But then again, a bad email sender’s reputation can be caused by so many reasons that trying to fix it may extend to the complete overhaul of your mailing campaigns. With this in mind, you might want to focus on the more specific metrics you can quickly fix.

Email Authentication Protocols

Verifying that the email belongs to you is a big deal for the ISP because it prevents the subscriber from phishing and other malicious practices. Most ISPs will block emails that do not employ an authentication protocol, so you must surely get one.

There are two major email authentication protocols:

Sender Policy Framework (SPF) SPF verifies whether you are authorized to send emails on behalf of your domain by checking your IP address against the list of authorized IP addresses (the list is provided by the domain owner).
DomainKeys Identified Mail (DKIM) DKIM verifies your domain and ensures the email content hasn’t been changed in transit. Your domain adds a DKIM signature header to the email, and the subscriber’s server verifies this signature using the public key from your DNS records.

In addition to SPF and DKIM, there is a higher-level authentication protocol, DMARC, and a visual enhancement protocol, BIMI.

  • DMARC provides instructions on how to handle emails that fail to comply with SPF and DKIM
  • BIMI allows you to display your logo next to your email, making your brand more recognizable in the inbox

Here’s how BIMI-optimized versus non-optimized emails look on mobile:

An inbox featuring BIMI-optimized emails

Here’s more about email authentication protocols:

Comparison of the four email authentication protocols - SPF. DKIM, DMARC, and BIMI - by protection level, implementation complexity, benefits, and dependency

Domain and IP Address Reputation

Having a common IP with other senders puts you at risk of receiving penalties based on someone else’s actions. However, getting a dedicated IP easily solves the problem.

The same applies at the domain level, with the only difference being that your domain-level reputation will affect all the IP addresses that belong to this domain. For example, if you’re sending emails from three IP addresses on the domain “,” the reputation scores of these addresses will be somewhat interconnected.

How To Improve IP and Domain-Level Reputation

In the ISP’s eyes, mailing volume and frequency are paramount. Whether you send too many emails, send them at random times, from a new IP address, or switch IPs and ESPs, this may be flagged as suspicious behavior.

Likewise, overdoing with clickbait subject lines, links, or unusual formatting may lead to blocking or throttling your emails, especially if the engagement rates are low. A no less important factor is your reputation history – the worse it is, the higher the risk.

Here’s how you can improve your IP and domain-level reputation:

Start slow When sending emails from a new IP address, start slow so the outreach looks natural to the ISP. Hit your most active subscribers first so they engage with your emails, allowing you to ramp up the volume,
Adjust mailing frequency by engagement It’s only natural that the ISP frowns upon anyone sending low-engagement emails to the left and right. Increase the volume proportionally to the engagement to avoid suspicion from the ISP.
Coordinate different departments An outreach schedule that factors in all outgoing emails will help you avoid overload on a particular day. Make sure all your departments know when they should send emails and how these emails fit the bigger picture.

Email Size, Design, and Content

ISPs are constantly getting better at evaluating emails beyond technical parameters like size and format. There may not be a universal recipe for quality emails, but the base Google guidelines are here for text emails and here for emails that contain more than just plain text.

Email and attachment sizes for ESPs - Gmail, Outlook, Yahoo Mail, Apple Mail, and AOL Mail - and ISPs - Comcast, Verizon, AT&T, and Charter.

But then again, a quality email takes more than just the right size. Not only should it be customized to the subscriber’s needs and wants, but it should also follow some basic rules like the ratio of text, HTML elements, images, and links.

Here are a few common techniques to improve email deliverability:

Text-to-link ratio Too many links may overwhelm the reader and trigger spam filters, so it’s best to include no more than one link per 100 words of text.
Text-to-HTML ratio While HTML helps provide structure and visual appeal, it should not take up more than a third of the text volume.
Text-to-images ratio As great as images and GIFs are in emails, they shouldn’t make up more than half of your message. If sending an image-only email is your strategy, include alt text for images so users can see what the email is about if the image is not displayed.
The proper wording The overuse of terms related to sales, promises, and scarcity – free, immediate, limited, expires, get paid – as well as exclamation marks, ALL CAPS, and symbols like $ or % can trigger spam filters.
Links Broken, unreliable, excessive, and mismatched links are a big red flag for any ISP. Use descriptive anchors – check out this product instead of click here – and include no more than 3 links in short and 5 in longer emails.

I won’t even mention the dirty tricks from the dawn of the Internet, like masked links that match the background or tiny-font links – any of these will quickly spell a disaster for your email campaign. On the other hand, you might divert from the rules to a certain extent if your message is valuable, customized, and well-timed – a smart ISP will likely pass it through.

Email List Hygiene

Building a subscriber list is only half the job—the other half is maintaining it healthy as new campaigns unroll and more data comes in.

Some of your subscribers will eventually disengage, some will change their preferences, and some might just want to unsubscribe—and you must ensure everyone gets what they want whenever they want it.

Here’s how you can maintain an email list hygiene:

Remove irrelevant emails Remove all hard bounces instantly and soft bounces after a few unsuccessful delivery attempts. Clean your email list regularly.
Use double opt-in to ensure subscriber quality Ask users to confirm their registration to ensure you only send emails to high-intent subscribers. Double opt-in will save you tons of resources down the road.

At the same time, don’t overdo the cleaning. Not all inactive subscribers dislike you—some might be just taking a break and will reengage soon. With this in mind, develop the optimal re-engagement email sequence, gradually decreasing the engagement until you can be sure you can remove them from the list.

Quality emails sent at the right time usually have low unsubscribe and complaint rates. In fact, as many as 57% of users unsubscribe because they are flooded with emails from the same brand, while 39% claim they receive irrelevant information.

Here is why consumers unsubscribe from marketing emails:

Statistics on the reasons why users unsubscribe from marketing emails

Source: Statista

Spam Traps

With around 45% of all emails being spam emails, ISPs go the extra mile with setting pristine spam traps – non-existing email addresses that help identify senders who’ve bought or scraped their mailing list.

Here’s how pristine spam taps work in practice:

  1. The ISP places fake email addresses on various websites
  2. Your automated script unknowingly collects fake addresses
  3. Sending emails to spam traps identifies you as a spammer


Buying or scraping emails is a bad idea, especially if you don’t verify these emails.

But there’s a more refined spa trap: recycled spam trap, a previously valid email address that is now abandoned. Recycled spam traps identify senders with poor email list hygiene.

Comparison of pristine and recycled spam traps by four parameters: legitimacy, goal, common sources, and sender's reputation damage

Subscriber Engagement and Feedback

Everyone wants subscribers to be happy—happy subscribers buy more—so engagement and feedback are the most important success indicators. At the same time, measuring these two accurately and timely might only be possible if you dig beyond your email campaigns.

With this in mind, I’d suggest using Phonexa’s E-Delivery, an omnichannel client management system combining SMS automation and email deliverability software, and seven other performance marketing products to cover the customer journey from top to bottom.

Take a product tour

Here’s what E-Delivery does for email marketers and affiliate mailers:

  • Ensures your emails will land in the inbox, even for bulk campaigns
  • Engages subscribers based on the omnichannel data collected with other Phonexa’s tools
  • Designs personalized emails and ensures the optimal send time and volume
  • Crafts compelling retargeting email and SMS campaigns
  • Detailed email deliverability reports and extra features like custom tracking

This unique set of email deliverability tools automates your email campaigns while making it easy to adjust the narrative to every subscriber. Likewise, you can A/B test your campaigns, leverage all major ESPs, and synergize E-Delivery with Phonexa’s other seven proprietary performance marketing products.


Personalization is among the top factors affecting email deliverability, although the correlation is difficult to measure. And it all starts with a subject line: 65% of marketers personalize subject lines in at least half of their emails.

Great subject lines can increase clicks, but a more challenging task is personalizing the body of the email: design, structure, wording, CTAs, and timing. To factor in all these parameters, you need deeper customer insights, which is another reason to have a comprehensive lead management system like Phonexa.

At Phonexa, we synergize email deliverability solutions and lead management tools:

Covering every marketing avenue with a single software suite has obvious benefits: you’re fast, effective, reliable, and protected from fraud. More importantly, you know customers much better than if you relied on email campaigns only.

Speaking of knowing your customers, one special instrument for digging deep into your audience is the web analytics and data visualization tool HitMetrix, which is also included in the Phonexa software bundle.

HitMetrix collects and analyzes website behavior so you can know what users had been doing on-site before they subscribed and what prevented others from subscribing to your newsletter:


Last but not least, you can test your email campaigns for free with our proprietary predictive modeling software. As you collect data on your web and call leads, you can put it into a mathematical model that calculates the campaign’s success chance under this very special set of conditions – and you can repeat the process until you know the winners.


Improve Email Deliverability with Phonexa

Phonexa’s all-encompassing performance marketing software suite will ensure your emails reach their destination and are well-coordinated with other marketing avenues, such as SMS or affiliate marketing. You will squeeze the most out of every lead and prospect.


Phonexa grants you eight unique performance marketing tools at a single price starting at $100 per month, but you don’t have to overpay either. The subscription plans are customizable, and you can get a preliminary estimate using this online calculator.

Here’s a screenshot from the insides – all tools within a single dashboard:

Phonexa software suite's insides

Here are the eight tools I’m talking about:

LMS Sync Lead tracking & distribution
Call Logic Call tracking & distribution
E-Delivery Bulk email & SMS automation
Cloud PBX Cloud phone system
Lynx Click tracking
Opt-Intel Suppression list management
HitMetrix User behavior recording & analytics
Books360 Automated accounting

Build your plan to grow your email deliverability, or book a demo to learn more about Phonexa.

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Frequently Asked Questions

What is email deliverability?

Email marketing deliverability shows how many emails, in percentage of total emails sent, hit the subscriber’s inbox. For example, if 9,000 out of 10,000 emails reach the inbox, the deliverability rate is 90%.

Why is email deliverability important?

Email deliverability shows your outreach potential – how many clients you will likely be able to reach via email. Email deliverability rates correlate with your sender’s reputation, quality of emails, legal compliance, and whether your emails are relevant to the recipients.

What is email delivery?

Email delivery shows the percentage of your emails delivered to the subscriber’s mailbox—any folder, including the spam folder. Email delivery rates are always higher than email deliverability rates, as the former also count emails that hit the spam folder or the promotions folder.

What is a good email deliverability rate?

A good email deliverability rate is around 95%, or 10% higher than the average across industries. The higher the inbox delivery rate, the better, as these emails have a higher chance of getting clicks and conversions.

What is a good email delivery rate?

Your average email delivery rate across campaigns should be 98% or higher, indicating proper email list hygiene and adherence to the guidelines. Since February 1, 2024, anyone issuing over 5,000 emails per day must meet some additional requirements.

What is a good spam complaint rate?

Every EPS and ISP has its own spam complaint benchmarks, but the rule of thumb is that a good spam complaint rate is 0.02% or lower. In practice, this means that for every 10,000 emails sent, no more than 2 emails should be marked as spam. A spam complaint rate of 0.1% is already quite dangerous, potentially leading to trust issues and declining deliverability rates.

For more information, check these official 2024 anti-spam updates from Google and Yahoo!

Got Questions?

Get in touch! We are available 24/7.

Oleksandr Rohovnin avatar
Oleksandr Rohovnin
Content Marketer

Oleksandr Rohovnin is a Content Marketer at Phonexa. His passion is digital marketing, innovative technologies, and – above all – distilling vast amounts of complex information into engrossing narratives anyone can relate to. At Phonexa, Oleksandr stokes passion for marketing automation and lead generation in every story he curates.

Education: Zaporizhzhya National Technical University

Expertise: Digital marketing, affiliate marketing, call tracking, lead tracking, insurance


  • 8+ years of writing and editing experience in B2B and B2C

  • Unconventional synergy of writing talent and technical knack

  • Avid proponent of sports, gaming, and reading

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