Email and web-safe fonts
In email, we should always use web-safe fonts for all html text — body copy, ISI, references, footer, etc.
This almost always means Arial/Helvetica.*
Fun(?) fact: when a developer programs an email, they set the text as simply, "font-family: sans-serif" — Windows interprets this as Arial, and Mac OS and iOS interpret it as Helvetica. At a small size on screen they're virtually identical.
(The history of Arial and how it was created by Microsoft as a knockoff of Helvetica is pretty fascinating; Google it!)
There are lots of lists online of "web-friendly" fonts — most of them are outdated and/or simply wrong. For one thing, these lists often don't account for mobile devices.
*Note: Arial Black, Arial Narrow, etc are separate fonts from Arial and are not web-safe. In email, we can only use Arial regular, Arial bold, and Arial italic.
But why are we stuck with Arial?
When a user receives an email, the html file tells the device what font to use to display the content. The recipient must have that font installed on their device in order to display the text with the correct font. Arial(/Helvetica) is one of the (very!) few fonts that we can safely say is installed on everyone's device. If we shoot for a fancier font, and the user doesn't have it installed, the text will default to some other font, usually Times New Roman (gross!). We can program the email to first try for a fancier font and then default to a specific backup font, e.g. Arial, but that comes with a few challenges...
If you're in the world of pharma like I am, we generally have to submit our creative work to the client's med-legal team for approval, and most of these teams require that what we submit in layout will be exactly the same for all users. These med-legal teams are often so strict that even the idea of showing the piece to some users with one font and other users with a different font is something that they simply won't allow. So if we're required to show the same thing to all users, we're stuck with Arial.
What about Google fonts?
We cannot use Google fonts (reliably) in email. They're great for literally every other digital medium! The problem with Google fonts in email goes back to the point about our clients' med-legal teams. Google fonts are not supported in Outlook. So if you design and program the email with a Google font, some users will be able to see that font (on webmail, phones, etc), and Outlook users will not. Our client's med-legal people simply do not allow this in most cases. So, again, we're stuck with Arial.
But we want to use our brand font!
In email, we can only use brand fonts in graphical elements, like a header, or callout, or CTA button. But it is always better to avoid this since images won't display for a large percentage of users. Arial will perform better, across the board, for all users.
What are the other web-safe fonts?
The list of fonts that are truly web-safe across platforms is very short. Here they are:
That's really all of 'em! That's the full list of fonts that are 100% supported for emails on Windows, Mac OS, and iOS. This is the reason that, for emails, we almost always go with Arial/Helvetica. Verdana is a very distant second. There is no third.
Android phones handle fonts differently!
On Android, Arial and Verdana default to Droid Sans-Serif. Times and Georgia default to Droid Serif. Courier defaults to Droid Monospace. That's it. Trebuchet MS is not supported.
Look at consumer brands' emails
Check out some emails you've received from big consumer brands, e.g. (making up this list off the top of my head) Amazon, Netflix, Seamless, Uber, DoorDash, Facebook, Hulu, Instagram, Etsy, eBay, etc etc etc.
They all use Arial.
If there was a way to easily, reliably use brand fonts in emails, these gigantic brands would be doing it.
For email, Arial is the way to go.
It's one of those things I've been saying since probably around 2009 and I can't believe I'm still saying it in 2024, but here we are. Email is a technology that changes very, very slowly, if we are held to the lowest common denominator of supporting Outlook, which, in pharma anyway, we absolutely are.
– Manning
Questions/comments? Feel free to contact me at manning@manningkrull.com. I update these articles pretty frequently — best practices evolve over time as the world of digital quickly changes, and I always welcome insights from others.