Font File Converter Hub: EOT, OTF, TTF, WOFF & WOFF2

Five Extensions, Two Genuinely Different Ways of Drawing a Letter

A font file stores the outline of every letter, number, and symbol in a typeface, but "outline" doesn't mean the same underlying math across every format here. TrueType, the basis for TTF and one of two possible flavors of OTF, was developed by Apple in the late 1980s and describes each letter's curves using quadratic Bézier curves, stored in a font's glyf table alongside supporting tables named cvt, fpgm, loca, and prep. OpenType, jointly developed by Microsoft and Adobe, can wrap either that same TrueType outline data or an entirely different outline system: PostScript-style cubic Bézier curves, stored in a CFF (Compact Font Format) table instead of a glyf table.

WOFF and WOFF2 aren't outline formats at all — they're wrapper containers built specifically for web delivery, holding compressed TrueType or OpenType outline data inside, the same way a ZIP archive holds files without changing what's inside them. EOT, Embedded OpenType, is a fifth, historically distinct case: a Microsoft-created wrapper built in 2007 specifically for Internet Explorer, with its own compression scheme and, unlike the other four, a built-in digital rights management mechanism controlling how the embedded font can be reused.

Why Two Fonts That Look Identical Took Wildly Different Effort to Make

Hinting, the process of adjusting how curves render at small pixel sizes so letters stay crisp rather than blurry on lower-resolution screens, works completely differently depending on which outline system a font uses. TrueType/glyf fonts can contain extremely detailed, pixel-level hinting instructions specifying exactly how each individual glyph should render down to specific pixels, and building good hints this way is a genuinely laborious task requiring years of specialized expertise. OpenType/CFF fonts take a much lighter approach, with hints that provide only general information about the font's main features rather than pixel-precise instructions — a real, documented consequence of this difference is that hinting a CFF font typically takes less than one-tenth the time and expertise that properly hinting a TrueType font demands.

This is exactly why a font foundry's choice of outline format isn't cosmetic: a foundry aiming for the widest possible small-size legibility on older, lower-resolution displays has historically leaned toward TrueType's detailed hinting model, while foundries producing typefaces mainly for high-resolution modern screens and print, where aggressive pixel-level hinting matters less, often favor OpenType/CFF specifically because it reaches a finished, well-hinted font faster.

What Each Format Trades Away for What It Gains

• Gain, TTF/OTF — desktop installability: both install directly into an operating system's font list for use across every installed application, something WOFF, WOFF2, and EOT were never designed to do.
• Gain, WOFF2 — dramatically smaller web payloads: Brotli-based compression delivers roughly 30 to 40 percent smaller files than WOFF, and up to 50 percent smaller than an uncompressed TTF or OTF.
• Lose, EOT — any future beyond legacy Internet Explorer: its DRM-locked design and lack of adoption by any other browser, including Microsoft's own Edge, left it with no forward path once IE was retired.
• Gain, OTF/CFF — faster foundry production time: lighter hinting requirements mean a well-finished OpenType/CFF font typically reaches release faster than an equally polished TrueType font.
• Lose, WOFF/WOFF2 — no direct desktop installation: both are web-delivery wrappers only; getting a usable desktop font back out requires converting to TTF or OTF first.
• Gain, TTF — the deepest small-size hinting control: pixel-level hinting instructions can outperform CFF's lighter approach specifically at small sizes on lower-resolution displays.

Which Format Actually Loads Where, Documented by Real Support Dates

WOFF2 now carries over 97 percent global browser support, with every current release of Chrome, Firefox, Safari, and Edge implementing it, which is exactly why it's the standard first choice for web font delivery today. WOFF, its predecessor standardized earlier by the W3C, remains a reasonable fallback for a small number of older browser versions still in limited use. TTF and OTF both install natively across Windows, macOS, and Linux desktop environments and are read directly by design software like Photoshop, Illustrator, and InDesign, but neither is a first choice for web delivery, since browsers have to do more work parsing and rendering an uncompressed desktop font format compared to a purpose-built web wrapper.

EOT sits entirely outside this modern landscape: Microsoft's own Web Embedding Fonts Tool (WEFT), the utility built specifically to generate EOT font objects, saw its last release, version 3.2, on February 25, 2003, and Microsoft had stopped offering it for download entirely by 2019. EOT itself only ever rendered inside Internet Explorer versions 4 through 11, and Microsoft never added support for it in Edge, meaning the one browser lineage that ever read this format natively is now retired, with Edge's "IE mode" compatibility feature, supported through at least 2029, standing as the only realistic remaining context where it might still matter.

Why a Site Using WOFF Instead of WOFF2 Loads Measurably Slower

A concrete, checkable example from real font benchmarking makes the WOFF2 advantage specific rather than vague: Roboto Regular, a widely used typeface, runs about 168 kilobytes as an uncompressed TTF, roughly 85 kilobytes as gzip-compressed WOFF, and around 53 kilobytes as Brotli-compressed WOFF2 — a real, measured 38 percent reduction from WOFF to WOFF2 on the identical typeface. A typical page loading four separate font files can see a payload difference of well over 100 kilobytes depending purely on which of these two web formats it serves, a real and measurable page-speed cost, not a rounding difference.

The practical fix for a site still serving only WOFF, or worse, raw TTF or OTF directly to browsers, is generating WOFF2 versions of every font in use and listing them first in the CSS @font-face declaration's src list, with WOFF kept only as a fallback line for the shrinking population of browsers that predate WOFF2 support — since every currently maintained browser reads WOFF2 natively, that fallback line goes unused by the overwhelming majority of visitors today.

Five Font Formats, Compared on Real Technical Grounds

Straight Answers Before Converting Between These Five Formats

Do TTF and OTF actually use different math to draw letters?
Sometimes. TrueType-flavored fonts (including many OTFs) use quadratic Bézier curves in a glyf table, while CFF-flavored OTF fonts use cubic Bézier curves in a separate CFF table — genuinely different outline systems, not just different file extensions.

Why does hinting one font take so much longer than another?
TrueType hinting supports extremely detailed, pixel-level instructions that take years of expertise to do well, while OpenType/CFF hinting is deliberately lighter, typically taking less than a tenth of the time for a comparable result.

Is WOFF2 always better than WOFF for a website?
For any currently maintained browser, yes — WOFF2's Brotli compression measurably outperforms WOFF's gzip-based compression, often by 30 to 40 percent on the same typeface. Keep WOFF only as a fallback for older browser versions.

Is there ever a real reason to generate an EOT file today?
Only for an internal corporate site still running inside Microsoft Edge's "IE mode," a compatibility feature supported through at least 2029. No public website needs EOT, since no actively maintained browser reads it.

Can I install a WOFF2 file directly like a regular font?
No. WOFF and WOFF2 are web-delivery wrappers, not installable desktop formats — converting to TTF or OTF first is required to install the font in Windows, macOS, or design software.