Font Formats Explained: TTF, OTF, WOFF, WOFF2 — The Complete Guide

Four font formats dominate the modern web and desktop design world: TTF, OTF, WOFF, and WOFF2. Each serves a different purpose. Downloading a font and ending up with all four versions in a zip file is common — and confusing. This guide explains exactly what each format is, when to use it, and how to convert between them.

TTF (TrueType Font): The Universal Desktop Format

TTF was co-developed by Apple and Microsoft in the late 1980s as a direct competitor to PostScript's Type 1 format. It uses quadratic B-spline curves for glyph outlines and includes its own hinting system for rendering at small sizes on low-resolution screens.

Where it shines: TTF has the broadest compatibility of any font format. It works on Windows going back to Windows 3.1, on every version of macOS, on Linux, on Android, and in embedded systems. Cricut cutting machines, embroidery software, and older apps often require TTF specifically.

Limitations: The TTF container format originally wasn't designed with rich OpenType features in mind. While modern TTF files can technically embed ligature and alternate glyph tables, foundries more commonly package those features in OTF.

File size: TTF is the baseline — other formats are measured relative to it. A 100KB TTF is roughly 65KB as WOFF and 50KB as WOFF2.

OTF (OpenType Font): The Modern Standard

OpenType was developed jointly by Adobe and Microsoft in the 1990s as a next-generation font format. The OTF container can hold either TrueType outlines (quadratic) or CFF/PostScript outlines (cubic). Professional fonts from type foundries almost always ship as OTF today.

Where it shines: OTF is the standard for professional design work. It can package hundreds of alternate glyphs, ligatures, swashes, stylistic sets, and contextual substitutions in a single file. Adobe InDesign, Illustrator, and Photoshop expose all of a font's OTF features through their glyph panels. Modern operating systems apply ligatures and other features automatically from OTF files.

Limitations: Slightly worse compatibility with very old software (pre-2000 apps). Some cutting machine software and niche platforms still prefer TTF. If your OTF won't show up in a specific app, converting to TTF usually solves it.

CFF vs TrueType OTF: OTF files with CFF outlines are sometimes smaller for complex, large-character-set fonts (especially CJK fonts). OTF files with TrueType outlines are larger but may render better on older Windows systems.

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WOFF: The Standard for Self-Hosted Web Fonts

WOFF (Web Open Font Format) was developed by Mozilla, Microsoft, and Opera as a container format specifically for web font delivery. It's not a new font format in terms of outlines — it takes TTF or OTF data and wraps it in a compressed package with a WOFF-specific header.

Where it shines: WOFF is the right format for CSS @font-face self-hosted fonts. It's supported in all modern browsers (and IE9+) and reduces font file size by about 30-40% compared to TTF or OTF. That smaller size translates to faster page loads, especially on mobile.

Limitations: WOFF files aren't installable as desktop fonts on Windows or Mac without first converting them back to TTF or OTF. They're web-delivery-only files in terms of practical use.

The Font Converter converts TTF and OTF files to WOFF, and also converts WOFF back to TTF or OTF for desktop installation.

WOFF2: Maximum Web Compression

WOFF2 uses brotli compression (the same algorithm behind Brotli-encoded web responses) instead of the zlib compression used by WOFF. This results in about 50% smaller file sizes compared to TTF — roughly 10-20% smaller than WOFF.

Where it shines: Best web performance. All modern browsers support WOFF2 (Chrome 36+, Firefox 39+, Safari 12+). For any web project targeting modern browsers, WOFF2 is the optimal delivery format.

Limitations: Slightly worse compatibility than WOFF (no IE support). Not installable as desktop fonts. Generating WOFF2 requires brotli compression support — the current font converter handles TTF, OTF, and WOFF; for WOFF2 generation, command-line tools like fonttools or online services like Transfonter are your options.

Best practice for web fonts: Serve WOFF2 as the primary format and WOFF as the fallback in your @font-face declaration — browsers will use the best format they can handle.

Which Font Format to Use: The Decision Guide

Use Case	Best Format	Reason
Installing on Windows/Mac	TTF or OTF	Both work; TTF for old apps, OTF for design software
Cricut cutting machine	TTF	Cricut Design Space on Windows reads TTF most reliably
Self-hosted web font	WOFF (+ WOFF2)	Compressed for faster load, browser-native support
Advanced typography in InDesign	OTF	Best support for ligatures, alternates, stylistic sets
Embroidery / cutting software	TTF	Older software typically requires TrueType
Maximum web performance	WOFF2	50% smaller than TTF; all modern browsers support it
Cross-platform compatibility	OTF	Consistent across Mac, Windows, Linux

For most personal and professional projects, keep the OTF for desktop use and convert to WOFF for web use. If you hit compatibility issues with specific software, convert to TTF as a fallback.

Frequently Asked Questions

Can I have both TTF and OTF versions of the same font installed?

Yes, technically. But the OS may display them as the same font in menus, or one may conflict with the other depending on internal font naming. It's generally cleaner to keep just one version per font family installed. If you want to try OTF features in design software but need TTF for other apps, keep OTF installed and convert to TTF only when needed.

What font format does Google Fonts use?

Google Fonts serves WOFF2 to modern browsers and WOFF as a fallback via their CDN. When you download a font from Google Fonts directly, you get TTF files — these are the desktop-installable versions. For web use, Google's CDN handles the WOFF2/WOFF serving automatically.

Why does a font have four files in its zip (TTF, OTF, WOFF, WOFF2)?

Font packages often include all formats so buyers can use the font in any context without conversion. TTF and OTF for desktop, WOFF and WOFF2 for web. Technically you could derive all others from any one of these using conversion tools — but shipping all formats saves the buyer the conversion step.

Is there a free way to convert fonts without uploading them to a server?

Yes. Browser-based font converters like the WildandFree Font Converter process font files locally in your browser — the font data never leaves your device. This matters for licensed fonts where you may not want to share the font files with third-party servers.