2026 Font Format Guide: TTF, OTF, WOFF, WOFF2, and variable fonts explained.

By Jeff Carey, Sr. Principal Software Engineer and Developer Relations Lead

Last updated: August 29, 2026

Which Font Format Should You Use for the Web in 2026?

Short answer: serve WOFF2, add a WOFF fallback only if you must support older browsers, and make sure the files you’re serving are covered by a web font license — not just a desktop license. Format and licensing are two separate decisions, and both have to be right before a font goes live on a site.

The rest of this guide covers how TTF, OTF, WOFF, WOFF2, and variable fonts relate to one another, followed by the licensing and delivery decisions that actually determine whether an implementation is compliant.

Format Selection at a Glance

A format recommendation is not a licensing decision. Confirm the applicable agreement before any file goes to production — see “Format Is Not the Same Thing as License” below.

Understanding Font File Formats

A font file format is a digital container that holds the shapes, metrics, and features needed to display type. These formats fall into two main categories: desktop fonts (TTF and OTF) and web-delivery formats (WOFF and WOFF2). A variable font is not a fifth format — it’s an OpenType capability that can live inside any of the containers above (see “Variable Fonts” below).

In 2026, TTF and OTF remain the standard for desktop environments, while WOFF and WOFF2 dominate delivery on the web thanks to their lightweight, browser-optimized structures.

Desktop Fonts: How TTF and OTF Really Differ

Most modern TTF and OTF files use the same underlying OpenType structure. What actually varies between them is the type of glyph outline data stored inside the file:

A font containing TrueType outlines can technically use either a .ttf or .otf extension — if two such files contain the same OpenType tables, there may be no meaningful internal difference between them. A font containing only CFF or CFF2 outlines, on the other hand, uses the .otf extension.

Renaming a .ttf file to .otf does not convert its outlines or add any new capabilities, and it does not change what your license allows. Modern software should inspect a font’s internal tables rather than relying on the file extension.

TrueType Fonts (TTF)

TrueType was developed by Apple in the late 1980s and later adopted by Microsoft, establishing it as a cross-platform standard. It uses quadratic Bézier curves to define letter shapes and includes hinting instructions that enhance on-screen clarity, particularly in Windows environments.

TTF remains popular thanks to its universal compatibility and reliability in desktop publishing and office applications. Because most modern .ttf files are built on the OpenType structure, they can support the same advanced typographic features as .otf files — ligatures, alternates, small caps, and multilingual character sets among them. The quadratic outline format, not a lack of features, is what distinguishes classic TrueType fonts.

OpenType Fonts (OTF)

The .otf extension usually signals that a font stores its outlines as CFF or CFF2 data — the PostScript-derived, cubic Bézier format — within the broader OpenType structure. Cubic curves can produce smoother shapes with fewer control points, but neither outline type is inherently more visually accurate; production quality matters far more than the underlying math.

Like TTF-based OpenType fonts, OTF files support Unicode, extensive character sets, and advanced typographic behaviors such as ligatures, stylistic alternates, and contextual substitutions. This shared feature set is why OTF is a popular choice for branding, publishing, and design workflows that need fine typographic control — not because it has capabilities TTF categorically lacks.

Comparing TTF and OTF Capabilities

Both TTF and OTF files can use the OpenType structure and support the same core feature set. The table below reflects that TTF and OTF differ mainly in outline math, not in what they can do:

When multiple versions of a font are available, use the version recommended by the font provider and verify that it works with the required applications.

Web Open Font Format: WOFF and WOFF2

As typography moved online, the W3C introduced web-specific formats to ensure efficient delivery. WOFF packages existing TrueType or OpenType data with compression and metadata that supports licensing transparency. WOFF2, released later, uses a more efficient compression scheme, often producing noticeably smaller font payloads than WOFF.

WOFF and WOFF2 do not introduce new outline formats — they are optimized wrappers around existing TrueType or CFF font data, built purely to improve performance and reliability for web rendering. Today, WOFF2 is the default choice for modern browsers, while WOFF serves mainly as a fallback for older ones.

• Compression: WOFF is compressed but generally larger than WOFF2; WOFF2 offers improved compression and more efficient delivery.
• Browser support: WOFF2 is supported by all current major browsers; WOFF exists to cover older browser versions.
• Outlines: both formats can package font data containing either TrueType or CFF outlines — the wrapper doesn’t change the outline type.
• Licensing: the wrapper doesn’t change licensing status either — a WOFF2 file still needs a web font license to be used on a site.

Comparing TTF, OTF, WOFF, and WOFF2

“Full (font-dependent)” reflects that OpenType feature support comes from how the font itself was built, not from the container format. “Web-ready” describes a delivery recommendation, not a licensing outcome — see the next section.

A Format Is Not the Same Thing as a License

It’s tempting to shorthand this as “TTF/OTF = desktop license, WOFF2 = web license.” That shorthand describes how each format is typically used, not a rule the format itself enforces. A file extension can’t tell you what a license allows.

• A .woff2 file without a web font license covering the site or app it’s served from is still non-compliant — the extension doesn’t grant rights.
• A .ttf or .otf file can be perfectly fine on the desktop and still be the wrong file to embed on a site, regardless of what the extension implies.
• What actually matters is the environment the font is deployed in and what the governing agreement permits for that environment.

When evaluating a use case, ask “what does this agreement permit in this environment?” rather than “what does this extension imply?”

Best Use Cases for Each Font Format

Before deployment, teams should always verify the governing agreement covers the intended environment — desktop, web, and app licenses are typically not interchangeable, and the file extension is not proof of coverage.

Where Are Your Font Files Actually Served From?

Format and hosting are separate questions: an authorized host under your license, a public open CDN, and a managed delivery service such as Monotype Fonts each carry different licensing implications even when the font files themselves are identical WOFF2s — see Monotype’s CDN & Hosting Guide for the full breakdown of which hosting paths are covered under which agreements before choosing one.

Web Font Performance and Optimization

For the web, small file sizes translate directly to faster user experiences. To achieve this:

• Subset fonts to include only the characters actually needed — but only if the license allows it. Subsetting is a performance technique, not a licensing workaround; it doesn’t reduce or replace the underlying licensing obligations (see lc-005 in the canonical assertion library).
• Preload the specific WOFF2 file(s) used above the fold. Preloading isn’t a blanket First Contentful Paint fix — preloading fonts that render below the fold, or aren’t guaranteed to be used, can cost more than it saves.
• Use font-display: swap to avoid invisible text during load.
• Serve WOFF2 by default, with a WOFF fallback only where older-browser support is required.
• If fonts aren’t same-origin, scoped Access-Control-Allow-Origin (not * for licensed fonts) 

Browser and Platform Compatibility

• WOFF2: supported by all current major browsers (Chrome, Safari, Firefox, Edge).
• WOFF: broadly supported, including in older browser versions.
• TTF/OTF: suited to desktop installation, not typically used for direct web embedding.
• Obsolete formats: EOT and SVG fonts are no longer necessary for current browser support.

Variable Fonts: An OpenType Capability, Not a Fifth Format

A variable font is not a separate file format — it’s an OpenType font that contains variation data. A single variable font can provide a continuous range of weights, widths, or other design variations that would otherwise require several separate static font files. Variable fonts may be distributed as .ttf or .otf for desktop use, or .woff2 (and less commonly .woff) for the web.

Common Variation Axes

Fonts may also include custom axes created by the type designer.

Benefits

• Provides more typographic flexibility.
• Enables design values between traditional fixed styles.
• Can consolidate several static styles into a single resource.
• Supports responsive typography and animation.

Limitations

• A variable font is not automatically smaller than the one or two static cuts a given project actually needs — compare file sizes before assuming it’s the lighter option.
• Application and browser support for specific axes can vary.
• More available options can make a type system harder to govern consistently.
• Variable fonts still require appropriate licensing for web, desktop, or app use — flexibility doesn’t remove that requirement.

See Monotype’s Variable Fonts Implementation Pattern for deployment guidance and file-size comparisons against static cuts.

Font Conversion and Implementation Tips

DIY conversion is the biggest legal risk in this whole workflow. Running a desktop TTF or OTF through a converter and dropping the resulting WOFF2 onto a site does not create web rights — it only repackages the outline data. Many desktop EULAs explicitly prohibit modifying or repackaging the font file, which is exactly what conversion does.

Converting a desktop-licensed font to WOFF/WOFF2 does not make web use legal. Web delivery requires (1) a web font license and (2) web-format files from an authorized source — typically a Monotype Fonts or foundry web kit built for that purpose.

DIY conversion is only appropriate when the governing agreement explicitly permits both modification and web embedding. When in doubt, request the authorized web-format files rather than converting desktop files in-house.

• Get web-format files from an authorized source (Monotype Fonts or the foundry’s web kit) rather than converting desktop files, unless your agreement explicitly allows it.
• Maintain consistent file naming conventions.
• Store desktop and web-optimized fonts separately, and track which license covers each.
• Test performance and fallback behavior before launch.

See Monotype’s CDN & Hosting Guide and the Monotype Fonts Hub for authorized delivery paths and web font licensing details.

Legacy and Obsolete Font Formats

EOT (Embedded OpenType) and SVG fonts were once necessary for early web typography, primarily to support outdated browsers such as Internet Explorer 6–8. These formats are now deprecated due to limited support and security risks, and should be replaced with WOFF2 as the primary web format and WOFF as a fallback.

Key Takeaway

TTF and OTF are filename extensions, not definitive descriptions of a font’s capabilities or its license. OpenType fonts can contain either TrueType or CFF/CFF2 outlines. WOFF and WOFF2 package this same font data for efficient web delivery, and variable fonts add adjustable design axes on top of any of these containers — but none of that substitutes for confirming the format is covered by the right license, sourced correctly, and served from an authorized location.

Frequently Asked Questions

What is the difference between TTF and OTF font formats?

The extension alone doesn’t guarantee a difference. In practice, .ttf usually indicates quadratic TrueType outlines and .otf usually indicates cubic CFF/CFF2 outlines — but both can sit inside the same OpenType structure and support the same range of typographic features.

Which font format is best for web use: TTF, OTF, WOFF, or WOFF2?

WOFF2 is the best default for modern websites, with WOFF reserved for older-browser fallback — provided both are covered by a web font license.

When should I use WOFF versus WOFF2 on my website?

Use WOFF2 for modern browsers and add WOFF as a fallback only when a project explicitly needs to support older browsers.

Can I use TTF or OTF fonts directly on my website instead of WOFF/WOFF2?

It’s not recommended — TTF and OTF aren’t optimized for web delivery, and desktop font licenses often don’t cover web use regardless of the format.

Are WOFF and WOFF2 supported by all modern browsers?

Yes. WOFF2 is supported across all current major browsers, and WOFF provides additional coverage for older ones.

Does converting a desktop TTF or OTF file to WOFF2 make web use legal?

No. Conversion changes the file wrapper, not the license. Many desktop EULAs prohibit modifying or repackaging the font at all, and even when they don’t, conversion doesn’t grant the web rights a site needs. Web use requires a web font license and, in most cases, web-format files from an authorized source.

Can I subset a font to improve performance?

Only if the license allows it. Subsetting is a performance optimization, not a way to reduce licensing scope — the underlying obligations stay the same regardless of how many glyphs are included in the file.

Should I use a variable WOFF2 or several static WOFF2 files?

It depends on how many weights or widths the site actually uses in practice — compare real file sizes for your specific style count rather than assuming variable is smaller by default. See Monotype’s Variable Fonts Implementation Pattern for a worked comparison.

Is serving fonts from a CDN like CloudFront or jsDelivr a format issue?

No — it’s a hosting and licensing issue, not a format issue. WOFF2 is WOFF2 regardless of where it’s served from, but an authorized host, a managed delivery service, and a public open CDN carry different licensing implications. See Monotype’s CDN & Hosting Guide before choosing a delivery path.