Best Email Fonts: Email-Safe Fonts, Web Fonts and Fallbacks

Your brand font is probably not what most of your subscribers see. Gmail ignores almost every custom font. Desktop Outlook ignores them too, and if the code is not set up carefully it swaps them for Times New Roman. So the “best email font” question is really two questions: what looks good when the font loads, and what your email falls back to when it does not.

This guide covers the email-safe fonts that render everywhere, how web fonts and fallbacks actually behave in Gmail, Outlook and Apple Mail, how to set up custom fonts in Klaviyo, and the sizes and spacing that make marketing emails readable on a phone.

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What is the best font for email?

For body copy, use a web-safe sans-serif such as Arial, Helvetica or Verdana. They are installed on almost every device, so they render the same in every inbox. Use your brand’s web font for headings and buttons, with a close web-safe fallback set, so Apple Mail readers see your brand and Gmail and Outlook readers still see a deliberate design.

That pairing is also what Klaviyo’s help centre recommends: a custom, branded font for headings and CTAs, and a web-safe font for body text.

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The email-safe fonts

These fonts ship with Windows, macOS and iOS, and Android has close metric equivalents, so they need no download:

Font	Type	Best for	Notes
Arial	Sans-serif	Body copy, the universal default	The safest choice there is
Helvetica	Sans-serif	Body and headings on Apple devices	Not on Windows; stack it with Arial
Verdana	Sans-serif	Small text, accessibility	Wide letterforms, very legible at 13–14px
Trebuchet MS	Sans-serif	Friendlier headings	Slightly more personality than Arial
Georgia	Serif	Editorial newsletters, premium brands	The best serif for screens
Times New Roman	Serif	Formal documents	Reads as “default”, rarely right for marketing
Courier New	Monospace	Codes, receipts, order numbers	Discount codes read clearly
Tahoma / Century Gothic	Sans-serif	Use with care	Klaviyo notes these are not preinstalled on iPhones

Two practical rules:

1. Always write a font stack, never a single font. font-family: Helvetica, Arial, sans-serif; tells the inbox to use Helvetica if it has it, Arial if not, and any sans-serif as a last resort.
2. Match the fallback to the shape of your brand font. A geometric brand font falls back better to Verdana or Trebuchet MS than to Arial. A serif brand font should fall back to Georgia, not Times New Roman.

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Email-safe fonts vs web fonts

Email-safe fonts are already on the reader’s device. Web fonts (Google Fonts, Adobe Fonts, your own self-hosted brand font) are downloaded from a server when the email opens. Most custom brand fonts are web fonts.

The problem is support. As of September 2026, based on Klaviyo’s “Understanding fonts in email” article and Caniemail’s @font-face data:

Inbox	Web fonts?	What readers see otherwise
Apple Mail (macOS) and iOS Mail	Yes	Your brand font
Outlook for Mac	Yes	Your brand font
Samsung Mail and the native Android client	Yes (most versions)	Your brand font
Gmail (web, iOS, Android)	No, except Roboto and Google’s own fonts	Your fallback
Outlook for Windows (desktop)	No	Your fallback, or Times New Roman if the code is not handled
Outlook.com and Yahoo	Inconsistent	Test; usually your fallback

For a typical DTC list, Apple Mail and iOS Mail account for a large share of opens, so web fonts are worth using. But Gmail is usually the second-biggest inbox, and it will never show your brand font. Your fallback is not a backup plan. It is what a big part of your list sees.

The Outlook Times New Roman problem

Desktop Outlook for Windows has a quirk worth knowing. Caniemail documents that when an element uses a font declared with @font-face, Outlook can ignore the rest of the font stack and drop straight to Times New Roman. Your carefully chosen Arial fallback never gets a look in.

The standard fix in hand-coded HTML is an Outlook-only style block that forces the fallback:

<!--[if mso]>
<style>
  body, table, td, h1, h2, h3, p, a { font-family: Arial, sans-serif !important; }
</style>
<![endif]-->

Another common approach is to wrap the @font-face declaration in a @media screen { } query, which Outlook for Windows ignores. If you build in Klaviyo’s drag-and-drop editor, the fallback you choose when adding a font handles most of this, but always check an Outlook test before you trust it.

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How to add custom fonts in Klaviyo

Klaviyo’s editor supports three kinds of custom font (steps from Klaviyo’s help centre, as of September 2026):

1. Open a text block, or the template’s Styles tab.
2. Click Add Font at the bottom of the font dropdown.
3. Choose the source:
   • Google Font: type the font name, choose a fallback, click Add Font.
   • Adobe Font: requires an active Adobe Fonts subscription. Paste the CSS address (it looks like https://use.typekit.com/abc123), choose a fallback and confirm.
   • Import Font: for self-hosted fonts. Host the font files on your own server with CORS enabled (the Access-Control-Allow-Origin header set to *), then enter the URL, font name, weight and style. Klaviyo recommends this route only if you have access to a developer.
4. Choose the fallback carefully. Every custom font needs one, and it is what Gmail and Outlook readers see.

Once added, the font is available across all your templates and your sign-up forms, which keeps email and pop-up typography consistent. Set it once in your brand styles so every new template starts from the right place.

Licensing check: a desktop font licence does not always cover web or email use. If your brand font came from a commercial foundry, confirm the licence covers self-hosting for email before you import it.

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Font size, line height and spacing for marketing emails

Fonts fail more often on size than on typeface. These are sensible defaults for ecommerce emails built at 600px wide:

Element	Size	Line height	Notes
Body copy	14–16px (16px preferred)	1.4–1.6	iOS Mail enlarges text under 13px, which can break layouts
Headings (H1)	26–32px	1.2	Bold or semi-bold
Subheadings	18–22px	1.3
CTA buttons	16–18px, bold	n/a	Live text, never text baked into an image
Footer and legal	11–12px	1.4	Still needs to pass contrast

Should email font size be 11 or 12? For personal and business emails typed in Outlook or Gmail, 11 or 12pt is standard, and 12pt is easier to read. Marketing emails are coded in pixels: 12pt equals 16px on screen, which is why 16px is the go-to body size.

Other details that separate a clean email from a cramped one:

• Keep line length sane. On a 600px template with padding, body text naturally lands at 60–80 characters per line. Do not widen the text column past that.
• Avoid light weights for body copy. A 300-weight brand font may look elegant in Apple Mail, but its fallback renders at a normal weight in Gmail, so your design shifts between inboxes. Pick weights that exist in both.
• Limit yourself to two fonts. One for headings, one for body. Three or more reads as untidy on a small screen.
• Check contrast. WCAG AA asks for a contrast ratio of at least 4.5:1 for normal text. Pale grey on white fails, and it fails harder in dark mode.

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Do not put your text in images

The fastest way to “use your brand font” is to bake headlines into images. It is also the most common design mistake we see in ecommerce accounts:

• Images get blocked or load slowly. The reader sees alt text, or nothing.
• Dark mode cannot adapt them. Klaviyo’s dark mode guidance is to use live text wherever possible, because inboxes can recolour text but not pixels in a picture.
• Text shrinks on mobile. A 600px image displayed on a phone is scaled down to roughly 60–70% of its size, so 20px text in the image lands at around 12–14px on screen. Our email dimensions guide has the maths.
• Accessibility and search. Screen readers cannot read it, and you cannot search your inbox for it.

Use images for photography and product. Use live text, in a proper font stack, for anything someone needs to read. The same applies to GIFs: keep the headline and CTA as live text around them.

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Default email fonts: Gmail, Outlook and Calibri vs Aptos

A few questions that come up constantly:

• What font does Gmail use? Gmail’s default compose font is its generic “Sans Serif” option, which displays as Arial on most systems. Google’s own interface uses Google Sans and Roboto.
• Which font does Outlook use? Microsoft announced Aptos as the new default font for Outlook, Word and the rest of Microsoft 365 in July 2023, and rolled it out to users from late 2023. It replaced Calibri, which had been the default for about 16 years.
• Is Aptos or Calibri better? Both are clean, modern sans-serifs. Aptos is slightly wider and rounder, which some readers find easier on screen. For marketing emails it is a moot point, since neither is guaranteed to be installed on a reader’s phone.
• Is Calibri or Arial more professional? Both are professional. Arial is safer for anything sent to people outside your organisation, because it is installed everywhere, including on Apple devices where Calibri may not be.

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Fonts for email newsletters and ecommerce campaigns

Some pairings that work well for ecommerce brands, each with a safe fallback:

• Clean DTC brand: a geometric sans web font (for example Montserrat or Poppins) for headings, falling back to Verdana or Trebuchet MS; Arial or Helvetica for body.
• Premium or editorial brand: a serif web font (for example Playfair Display or Lora) for headings, falling back to Georgia; Georgia or Helvetica for body.
• Supplement and health brands: clear, high-legibility sans-serifs for anything involving dosing, ingredients or directions. Legibility beats personality when someone is reading how many capsules to take.
• Plain-text style flows: use the inbox default or Arial and keep styling to a minimum, so the email reads like a personal note. See plain text vs HTML email for when that format wins.

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Best fonts for email signatures

Keep signatures in an email-safe font (Arial, Helvetica, Verdana or Georgia) at 10–12pt, and do not use images for your name or contact details. Cursive or script fonts only render if the recipient has them installed, so a script-style signature needs to be an image, which then gets blocked, flagged as an attachment, or rendered blurry. A clean sans-serif signature looks more professional in every inbox.

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The short version

Use email-safe fonts for body copy, your brand web font for headings and buttons, and always choose a fallback that matches your brand font’s shape, because Gmail and desktop Outlook will show the fallback. Set 16px body text, keep everything readable as live text, and test in Outlook before you trust any custom font. For the rest of the design system, see our guides on email dimensions and ecommerce email templates.

If your brand looks right in Apple Mail and wrong everywhere else, our email design and copywriting team builds Klaviyo templates with type systems that hold up in every inbox. Or book a free Klaviyo audit and we will show you how your emails actually render.