What percentage of emails are viewed in HTML vs plain text?
Summary
What email marketers say11Marketer opinions
Email marketer from Sendinblue.com explains that plain text emails are easier to read on mobile devices and may get through spam filters better.
Email marketer from SuperOffice.com states that the general user experience with HTML emails is overwhelmingly positive. But it also states that a poor user experience with HTML is down to poor formatting, large images and cluttered designs. These all contribute to a poor user experience.
Email marketer from Quora.com responds that Plain Text is useful when you want your email to be read in its simplest form, without any additional effects of formatting. It is also helpful when you don't have the time to write a HTML email. Plain text emails may also be useful in cases where there is security concerns.
Email marketer from ActiveCampaign explains that you should always send HTML with a plain-text version. This allows your recipients to choose which version they prefer, and you won't lose conversions because you're alienating them.
Email marketer from HubSpot.com shares that mobile users accounted for 51.9% of all email opens. Optimising for mobile is a core part of email marketing these days and not doing so will potentially turn your subscribers away.
Email marketer from Email Geeks shares that the percentage of HTML vs plain text views varies by audience. B2C is mostly HTML. B2B has a higher prevalence of plain text, especially in high-security environments like large enterprises, healthcare, and financial companies, where it can be up to 10% or more as the txt version is often served as a security measure. Also notes that in plain text the tracking pixel is often omitted and would only load if someone pasted the url in their browser, meaning the sender doesn’t get the same feedback they do from HTML emails.
Email marketer from Campaignmonitor.com shares that the best format (HTML or Plain Text) depends on your target audience. HTML is generally preferred for its design capabilities. Plain text emails are easier to read on mobile devices and may get through spam filters better.
Email marketer from Mailjet explains that spam filters have become increasingly sophisticated and the inclusion of HTML is no longer an indicator of spam. You have to ensure that your IP address has a good reputation, is authenticated, has a low spam score and that your email complies with general regulations. If all is good, the fact you are using HTML doesn't make a difference.
Email marketer from Reddit.com responds that they've seen some users on Reddit mention that they configure their email clients to display plain text by default, but it's a minority.
Email marketer from Email Geeks shares that they have done tests in the past of click tracking links being different in the plain text mime version versus the HTML mime version and the clicks from the plain text version were extremely small.
Email marketer from Mailchimp.com shares that while HTML emails allow for branding and visual appeal, some recipients prefer plain text. They suggest considering your audience when choosing between HTML and plain text.
What the experts say6Expert opinions
Expert from Email Geeks explains that statistically, there are no email clients that don't support HTML, and any normal mail client will display the HTML version. There are a few rare special cases where the text/plain version will be used (crappy, old ticketing systems, obsolete smartwatches).
Expert from Spam Resource explains that most modern email clients are capable of rendering HTML emails, so the vast majority of users will see the HTML version.
Expert from Email Geeks suggests that if sending into .mil, some other bits of the feds, the more rightfully paranoid end of the cybersecurity industry, one should consider just doing text/plain.
Expert from Email Geeks shares that there is no way to see the text version in most mail clients, as the MUA is supposed to display the 'highest quality' version of the message it can, usually the text/html part.
Expert from Email Geeks notes that it used to be .mil domains disabled HTML capabilities in email.
Expert from Word to the Wise notes that there are still some people using Text Only, therefore having some form of text in your email makes sense.
What the documentation says5Technical articles
Documentation from EmailToolTester explains how to test email deliverability rates. They state that Plain-text email is far less likely to be flagged as spam as it is often perceived as more safe.
Documentation from Microsoft.com states that Outlook will display HTML emails by default if the email client is capable of rendering HTML.
Documentation from Litmus.com provides data on email client market share, with Apple Mail, Gmail, and Outlook being the most popular. All of these support HTML email rendering.
Documentation from IETF.org explains the use of MIME to define content types in emails, including text/plain and text/html. text/html offers various rich styles that plain text can't replicate.
Documentation from StackOverflow explains that a HTML email that isn't coded to standards will not render as expected on the client end. The main reason an email is not coded to standards is that various platforms read and use code differently.