Email Deliverability Test A Detailed Look at the Best-Performing Tools

Email deliverability can really make or break an email marketing campaign. Most marketers know the theory behind boosting email deliverability rates – building and managing clean lists, keeping subscribers engaged, developing a good sender reputation, and so on.

But many also know from experience that you can do everything by the book and still have your emails mysteriously disappear after being sent.

Based on our bi-annual email deliverability test, we’ve confirmed what many marketers have long suspected – different email marketing services do have different deliverability rates. And the differences, in some cases, are quite startling.

As a result, we’ve decided to share our results, and have committed to performing regular tests to make sure our results are always up to date. We’ll continue to add them to this page with each round of tests to show you who has got the best email deliverability!

Because we believe email deliverability should be an important factor when deciding on which email tool is right for your business, we’ve also now added this as a criterion to each of our reviews.

Email Service Providers: Average Deliverability Rate

Over the years, we’ve seen fluctuations in the deliverability of the email service providers (ESPs) we monitor. This table gives you the average scores from our last three email deliverability tests (approximately a year and a half).

We're happy to see that popular email marketing services like Mailchimp and Hubspot, saw a slight increase over the last two rounds. It's safe to say that in previous rounds we’ve been left a little disappointed with their scores. 

MailerLite left us starstruck with an average deliverability rate of 95.4% over the last three rounds. They also scored the highest deliverability rate of this round, finishing the test with a whopping 96.5%. 

And due to their magnificent scores, we presented them with two well-deserved awards: 

You can find the results from all our tests in the table below.

What Is a Good Email Deliverability Rate?

Anything above a delivery rate of 89% is considered a good deliverability rate according to our methodology. Rates from 88 to 83% are considered acceptable. Any rate lower than that is considered poor.

A correctly delivered email is defined as an email that arrives in the recipient's inbox, which includes the promotions folders that some email providers provide (e.g. Gmail). Undelivered emails are those that land in spam or do not arrive at all (e.g., bounced messages).

The average deliverability rate in our tests is 85.7% across all tested email service providers currently.

Email Deliverability Test: Results Over Time

These rates represent an average derived from the five email deliverability tests in each testing round.

Provider	Aug 2017 %	Mar 2018 %	Jan 2019 %	July 2019 %	Feb 2020 %	Sept 2020 %	Mar 2021 %	Oct 2021 %	Apr 2022 %	Jan 2023 %	Round 11 (June 2023)
ActiveCampaign	85.8	96	97	93.8	90.2	73	91.1	91.6	90.2	93	93.1
AWeber	80.3	79.8	75.6	80.4	85.4	83	77.6	72.1	71.8	92	93.2
Benchmark	63.9	75.8	49.2	41.8	45.2	66	75.1	49.6	40.3	40.1	62.8
Constant Contact	89.74	93	90.4	88	89.4	89	91.5	87.7	90.9	92.1	92.0
ConvertKit	92.1	88	81	91.4	60	95	96.3	93.6	88.7	81.5	91.3
Drip	89.14	89.8	Not tested	88.8	78.8	86	87.9	81.3	77.5	62	86.7
GetResponse	87.5	78	80.6	85.4	75.6	86	83.8	76.1	82.9	87.4	91.3
MailChimp	87.52	82.6	81.6	90.6	81.6	91	86.9	85.2	85.9	92.7	95.5
MailerLite	77.6	89	92.6	94.8	78.4	90	96.9	95.7	98	91.7	96.5
Brevo (Sendinblue)	83.9	75.6	77.4	88.8	95.4	76	96.3	84.6	90	68.2	67.7
Mailjet	Not tested	Not tested	Not tested	84.8	94.6	94	89.6	77.8	86.1	84.2	80.6
CleverReach	Not tested	Not tested	Not tested	79.6	80.8	93	94.3	93.3	96.5	90.9	79.3
HubSpot	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	91.6	67.1	68.4	81.3	80.2
Moosend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	88.7	88.1	80.3	83.7	88.1
Omnisend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	85.1	85.3	67.6	72.5	87.9
Mailify	Not tested	Not tested	71.4	81.6	Not tested	Not tested	Not tested	Not tested	86.1	Not tested	Not tested
Overall Average	83.75	84.76	79.68	83.8	79.6	85.2	88.9	85.3	84.2	81	85.7

Note: The winners of each round are highlighted in bold

For an analysis of each of the individual test rounds, please follow these blog links:

Email deliverability test June 2023

Email deliverability test Jan 2023

Email deliverability test April 2022

Email deliverability test October 2021

Email deliverability test March 2021

As you can see, email deliverability rates can fluctuate over time. Even providers that have done consistently well (ActiveCampaign and MailerLite) have seen surprising results in the past. There are also those that consistently perform pretty badly (Benchmark).

For an analysis of the most recent results, see the blog post (and infographic) from our latest round of email deliverability tests.

The average deliverability for all tools combined was 85.7% in our latest round of tests. That means 14.3% of all emails have either gone completely missing or have been caught by popular spam filters. Unfortunately, the average was slightly higher than the last round (81%).

This is slightly better than the results achieved through Return Path's research, which found that the average global inbox placement rate was 83%.

Where Exactly Are Emails Landing?

It’s no surprise that there’s a direct correlation between low email deliverability rates, and high rates of email flagged as spam. Below is a breakdown of where exactly emails ended up (whether it was the main inbox, a secondary tab, spam folder, or if the emails went missing), in each test round we’ve completed.

Inbox placement rates June 2023

Inbox placement rates January 2023

Inbox placement rates April 2022

Based on these results, we can start to see some general trends:

• Benchmark tends to have a higher proportion of emails get filtered to spam. On the other hand, the same emails sent through ActiveCampaign and Constant Contact were much less likely to be marked as spam
• Providers are finding it increasingly more difficult to land emails in the main inbox, as more are directed to promotional tabs

Email Deliverability Test: Rates by Internet Service Provider (ISP)

Thanks to the email deliverability testing tool Glockapps.com, we were able to see just how well each newsletter service performed in getting delivered to the four main ISPs – Gmail, Microsoft (Outlook and Hotmail), Yahoo and AOL. Based on our results, you can see that certain ISPs definitely look more favorably upon some tools than on others.

Please keep in mind that Glockapps sometimes adds or removes ISPs/a particular email client to reflect their current popularity on the market.

Deliverability to Gmail

Provider	Aug 2017 %	Mar 2018 %	Jan 2019 %	July 2019 %	Feb 2020 %	Sept 2020 %	Mar 2021 %	Oct 2021 %	Apr 2022 %	Jan 2023 %	June 2023 %
ActiveCampaign	100	100	100	95	76	100	100	100	100	100	95
AWeber	100	100	100	83	81	92.6	92	92	100	100	95
Benchmark	50	100	0	13	34	100	100	100	96	100	100
Constant Contact	50	100	100	95	94	100	100	100	100	100	100
ConvertKit	100	100	100	95	80	100	100	100	76	100	95
Drip	100	100	Not tested	86.7	64	100	100	91	85	86	95
GetResponse	50	100	100	95	68	100	100	100	90	100	100
MailChimp	100	100	100	95	69	100	100	100	100	100	98
MailerLite	100	100	100	95	70	100	100	97	100	80	95
Brevo	100	100	100	95	93	100	100	95	98	80	100
Mailjet	Not tested	Not tested	Not tested	95	91	100	100	97	100	100	95
CleverReach	Not tested	Not tested	Not tested	89	82	100	100	100	100	100	95
HubSpot	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	100	100	100	100	95
Moosend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	100	100	100	100	100
Omnisend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	100	100	100	100	95
Mailify	Not tested	Not tested	80	84	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested

Deliverability to Microsoft (Outlook and Hotmail)

Provider	Aug 2017 %	Mar 2018 %	Jan 2019 %	July 2019 %	Feb 2020 %	Sept 2020 %	Mar 2021 %	Oct 2021 %	Apr 2022 %	Jan 2023 %	June 2023
ActiveCampaign	50	100	100	100	100	48.6	100	94.3	80	100	97.4
AWeber	0	18	0	56.9	60	61.4	24.3	7.1	2.9	95.7	98.7
Benchmark	0	0	0	33.8	23.1	51.4	71.4	0	0	0	94.5
Constant Contact	84.4	100	100	100	98.5	100	100	94.3	100	100	100
ConvertKit	84.4	69	75	95.4	0	100	98.6	95.7	98.6	40	96
Drip	0	100	Not tested	100	100	94.3	100	95.7	94.3	0	94.7
GetResponse	50	20	20	60	56.9	80	60	15.7	80	100	97.1
MailChimp	50	24	31	80	80	80	60	74.3	60	100	98.7
MailerLite	0	100	100	100	32.3	61.4	100	95.7	100	100	97.4
Brevo	50	7	0	78.5	98.5	100	100	95.7	95.7	100	40
Mailjet	Not tested	Not tested	Not tested	43.1	100	100	71.4	76.2	78.6	80	70.3
CleverReach	Not tested	Not tested	Not tested	100	63.1	98.6	98.6	95.7	97.1	100	96
HubSpot	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	94.3	16.1	27.1	95.7	89.2
Moosend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	98.6	94.2	80	100	100
Omnisend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	80	92.9	0	20	100
Mailify	Not tested	Not tested	16	75.4	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested

Deliverability to Yahoo

Provider	Aug 2017 %	Mar 2018 %	Jan 2019 %	July 2019 %	Feb 2020 %	Sept 2020 %	Mar 2021 %	Oct 2021 %	Apr 2022 %	Jan 2023 %	June 2023 %
ActiveCampaign	100	100	100	100	90	91.1	82	89	100	100	100
AWeber	100	100	100	100	100	100	100	89	100	100	100
Benchmark	100	100	100	20	7.5	20	40	0	0	23	0
Constant Contact	100	100	100	100	100	100	100	100	100	100	100
ConvertKit	100	100	97.5	100	97.5	100	100	100	100	100	100
Drip	100	100	Not tested	100	100	100	100	100	100	100	58
GetResponse	100	97.5	100	95	100	100	100	100	100	100	100
MailChimp	100	100	100	100	100	100	100	89	100	100	100
MailerLite	100	100	100	100	100	100	100	100	100	100	100
Brevo	100	100	97.5	100	82	0	100	78	100	20	20
Mailjet	Not tested	Not tested	Not tested	100	100	95.6	82	36	71	98	95
CleverReach	Not tested	Not tested	Not tested	100	87.5	97.8	100	100	100	80	47
HubSpot	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	98	100	100	100	100
Moosend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	100	100	100	100	100
Omnisend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	100	100	100	100	100
Mailify	Not tested	Not tested	80	85	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested

Deliverability to AOL

Provider	Aug 2017 %	Mar 2018 %	Jan 2019 %	July 2019 %	Feb 2020 %	Sept 2020 %	Mar 2021 %	Oct 2021 %	Apr 2022 %	Jan 2023 %	June 2023 %
ActiveCampaign	7.1	100	100	100	97.1	0	100	100	100	100	100
AWeber	100	100	80	100	100	100	100	100	100	100	100
Benchmark	0	80	100	20	0	20	40	0	20	0	0
Constant Contact	92.9	100	100	97.1	100	100	100	100	100	100	100
ConvertKit	100	100	100	100	97.1	100	100	100	100	100	100
Drip	100	100	Not tested	100	85.7	74.3	71	71	71	71	57
GetResponse	85.7	100	100	94.3	100	100	100	100	100	100	100
MailChimp	100	100	100	100	100	100	100	100	100	100	100
MailerLite	100	100	100	100	100	100	100	100	100	100	100
Brevo	85.7	100	100	100	100	0	100	80	100	0	0
Mailjet	Not tested	Not tested	Not tested	100	100	57	94	94	66	77	46
CleverReach	Not tested	Not tested	Not tested	17.1	100	94.3	100	89	91	80	40
HubSpot	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	83	100	100	100	97
Moosend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	100	97	100	100	100
Omnisend	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	100	100	100	97	100
Mailify	Not tested	Not tested	74.3	62.7	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested	Not tested

What does this mean? Well, if you have a good sense of who your subscribers’ email providers are (in an ideal world for email marketers, that would be Yahoo!), you might consider choosing a newsletter service based on this. Of course, that’s often difficult to know. Plus, as our results show, deliverability to ISPs can change over time.

It’s perhaps more useful to just keep an eye out for any red flags. For example, Microsoft has, in the past, applied more stringent filtering to inbound emails, and some newsletter services – such as Benchmark – still struggle to get through.

Gmail Promotions Tab vs Primary Inbox

While the newsletter services were generally able to deliver to Gmail mailboxes just fine, not all ended up in the Promotions tab. Nowadays, even emails that wouldn’t normally be considered ‘promotional’ are ending up in this folder.

Proportion of Gmail-delivered emails that ended up in Primary inbox.

Provider	Aug 2017 %	Mar 2018 %	Jan 2019 %	Jul 2019 %	Feb 2020 %	Sep 2020 %	Mar 2021 %	Oct 2021 %	Apr 2022 %	Jan 2023 %	June 2023 %
Mailerlite	100	100	100	74.67	9.64	15	20	15	22	26	40
Rapidmail	100	63	100	41.33	21.43	40	20	12	20	40	44.5
ActiveCampaign	–	–	–	94.67	15.71	60	60	40	80	97	21.5
Mailchimp	20	0	60	74.67	68.57	40	40	40	42	58	75.3
CleverReach	100	100	100	74.67	81.52	60	40	22	60	88	93.8
Brevo	77.14	100	100	94.67	80	80	80	75	78	80	58.5
GetResponse	60	100	100	74.67	15.71	0	0	0	20	18	60
Mailjet	–	–	–	54.67	48.57	60	40	35	40	60	60
Benchmark	100	100	0	6.66	13.57	25.71	20	0.17	0	0	76.7
Hubspot	85.72	50	100	62.67	72.86	–	20	100	6	60	58.5
Constant Contact	88.6	100	100	80	8.6	60	60	40	40	58.5	58.5
Aweber	100	100	100	64	81.19	18.57	37	18	22	72	95.4
Drip	100	100	–	72	44.29	60	60	49	69	46	36.9
Omnisend	–	–	–	–	–	–	60	60	60	78	40
Moosend	–	–	–	–	–	–	60	60	60	62	0
ConvertKit	100	100	100	74.67	45.36	60	40	42	18	58	78.5

Why do my Mailchimp emails go to Promotions?

Many Mailchimp users ask why their emails are going to Promotions. You can see that the rates have fluctuated over the years and that this question was more pertinent between 2017-2019 when 100% were ending up in the Promotions folder. However, nowadays, the percentage of Mailchimp emails ending up in Promotions isn't wildly different from other email marketing providers.

There’s no telling why some providers get sorted to Promotions and others don’t, as Google’s complex sorting algorithm is kept tightly under wraps. Ending up in Promotions is less than ideal, as your email is likely to get lost in the flood of emails that often make their way to that tab. Then again, if your email really is promotional and your subscribers are used to accessing emails from that tab, it may not be a problem. Furthermore, your email would be better off landing here than in the spam folder.

Our email deliverability test methodology

Our tests looked at some of the most widely-used email service providers:

• ActiveCampaign
• AWeber
• Benchmark
• Constant Contact
• ConvertKit
• Drip
• GetResponse
• MailChimp
• MailerLite
• Mailify
• Brevo
• Mailjet
• CleverReach
• HubSpot
• Moosend
• Omnisend

Using Glockapps.com, we ran our first round of testing in August 2017. This round comprised of 5 separate tests conducted over several weeks. We wanted to make sure all conditions were equal, so in each test, we:

• Set up a sender subdomain for each of the tested tools
• Authenticated the SPF records and DKIM records where available
• Used the same email (always text-based, sometimes with links, and sometimes without)
• Sent to the same seed list of approximately 80 email addresses (representing 28 ISPs worldwide, including Gmail, Outlook, AOL and Yahoo; weighted according to the popularity of the email service)
• Sent all emails within a half-hour period

Over three thousand emails later, we finally had the results from our first testing round. And we found some pretty big differences in email deliverability rates between providers – ranging from 64 to 92 percent!

Happy with the comprehensive deliverability report we received from Glockapps, we repeated this very same test round in March 2018, and from July 2019 onwards, we included an HTML email as one of our tests. The latest email deliverability test we carried out was in June 2023 and we plan to conduct, on average, one every 6 months.

Watch our Email Deliverability Best Practices video:

Why do some email marketing platforms perform so much better than others?

We’d love to know what the top performers' secret is – and we’re sure the other tools do too! What we do know is that the ISPs often have the last say on whether an email lands in an inbox. This means that they have to trust the mail server sending that email; in our case, that means the server used by the newsletter service.

If that same server also happens to be sending out emails for other clients that are considered ‘spammy’, the deliverability of your own emails could suffer. Newsletter services, therefore, make it a priority to maintain their server’s reputation. But some are clearly doing a better job of this than others.

Some email marketing services offer customers a dedicated IP address (rather than shared IP addresses), but these come at a high price, and are most likely not affordable for small businesses. In fact, a dedicated IP is not adapted for small senders (<3000 emails a day) and for irregular senders. You'll only need to consider opting for a dedicated IP address once you start sending over 3,000 emails a day / over 150K emails a month.

What does this mean for me?

With 50% of B2C users buying through marketing emails once a month, seeing your emails go undelivered could be costing you more than you thought and disrupting your whole email marketing strategy.

When choosing a newsletter service, there are obviously many factors to consider – price, features, usability, and so on. But with these results, we’ve hopefully made it easy for you to shortlist (or discard) a few based on potential email deliverability rates.

Note that we said ‘potential’ – there’s simply no way of knowing for sure how deliverability will play out for each business. Our test results can give you a general idea of what you can expect, and what things to look out for, but your own experience may be very different. If so, we’d certainly like to hear about it!

How to improve email deliverability

In spite of our best efforts to establish the same testing conditions for each tool, it’s true that other factors can play an important role. We have put together a complete guide on email deliverability best practices, where you can find more detailed information on the points below:

Email Authentication

As the sender, you have a responsibility to do your best to increase email deliverability by authenticating emails using SPF, DKIM and DMARC and following best practice guidelines for creating and sending emails. Usually, your newsletter tool will indicate whether all these records have been set up correctly. But you can also test your records with free tools like this SPF checker.

Email Verification

For the sake of their deliverability, no email marketer wants their emails bouncing.

There are tools to validate that an email address exists and can receive emails, which can help to avoid bounces and protect your sender reputation.

However, you can keep on top of list hygiene even without an email checker by unsubscribing inactive emails from your list. Some email marketing tools are stricter than others and will remove inactive emails from your list for you if they bounce a certain number of times.

Content

Try to only send marketing emails people actually want to receive, i.e. only send to fully opted in lists. Sending emails to non-permission-based lists will result in low open rates, high unsubscribe rates, and high spam complaints, all of which indicate an unsuccessful email.

These kinds of results can have a negative effect on sender reputation and will impact future deliverability.

Frequency

Find the right balance between sending too many and too few marketing emails to your subscribers. Remember that people are bombarded with tons of emails on a daily basis, so, in order to avoid inbox fatigue, only send what’s necessary.

You can even ask them to set the frequency at which they’d like to receive emails from you in their preferences. This can avoid spam complaints.

Monitoring activity

It’s not a good idea to have inactive people on your list as, if you’re sending emails to them regularly, this can affect sender reputation and impact deliverability.

Make sure to regularly check in with the less active people and give them the opportunity to re-engage or opt-out of future emails.

Check out these mass email service providers that help businesses send mass emails via SMTP servers or API.

The authors

Learn more about us

Inka Wibowo

Senior Content Manager

Hi, I'm Inka! I spent the earlier part of my career in agency land, helping businesses of all sizes get their email marketing campaigns up and running. Now, at EmailTooltester, I'm using my experience to help businesses like yours find the best email marketing services for your needs.

Charlotte Evans

Content Manager

Hey, I'm Charlotte! I've always been enthusiastic about helping others. After working for various tech startups and eCommerce businesses, I developed a strong passion for email marketing. Now, at EmailTooltester, I'm putting this knowledge to good use by recommending the very best digital tools for your business.

Learn more about us

We keep our content up to date

See latest updates

28 Aug 2023 - Added YouTube Video
24 Aug 2023 - Smaller updates and corrections
14 July 2023 - Updated Gmail primary inbox results
06 Jul 2023 - Infographic added
29 Jun 2023 - Updated with June 2023 results
10 May 2023 - Sendinblue is now called Brevo
27 Jan 2023 - Updated Sendinblue results
24 May 2022 - Added average deliverability of last 3 rounds section