Free Font File Inspector
Open a TTF, OTF, WOFF or WOFF2 file to see what’s inside, preview it, and check its licence and coverage.
What is a Font File Inspector?
This font file inspector opens TrueType, OpenType, WOFF and WOFF2 fonts and reads what’s inside them: family and style names, version, designer and licence, metrics, OpenType features, variable axes and named instances, and which characters the font covers.
It reads the font’s tables directly, checks each table against its checksum, flags restricted embedding and missing tables, and previews the font in your browser with sliders for variable axes. WOFF files are decompressed table by table; WOFF2 shows its table list and still previews.
Key Features
Names and Licence
Family, style, version, designer, foundry and licence.
OpenType Features
Every feature tag, with its registered name.
Variable Axes
Axes, ranges, defaults and named instances, with sliders.
Character Coverage
Mapped characters counted by Unicode block.
Integrity Checks
Checksums, required tables and embedding rights.
Perfect for everyone
- Web developers
- Designers
- Type designers and anyone checking a font before using it
How to Use the Font File Inspector
Open a font file from your computer or a downloaded font folder; there’s nothing to paste, and nothing to install first. The preview draws your own sample text in the font, and the other views read its tables, so you can check a font’s licence, coverage and features before you put it on a site or in a document.
Open the Font
A .ttf, .otf, .woff, .woff2 or .ttc file.
Try the Preview
Type sample text and move any variable axes.
Read the Details
Info, Features and Coverage cover what’s inside.
Run the Check
Confirm the file is intact and may be embedded.
Fonts, Opened
Each row is a font file of the kind people inspect before using it, from a small OpenType font to a variable font, web fonts and files that are broken in the ways downloads and edits break them. Each answer is this tool’s info, features, coverage or check, read from the file’s tables.
“NavioSans-Regular.otf”
“NavioSans-Regular.otf”
“NavioVariable-Regular.otf”
“NavioSansGreek-Regular.otf”
“NavioSans-BoldItalic.woff”
“NavioSans-Regular.woff2”
“NavioMono-Regular.otf”
“NavioSans-Regular (edited).otf”
“NavioSans-Regular.otf.part”
“logo.png”
Font File Formats
Font files share one table structure, called sfnt, inside different wrappers. The extension tells you the wrapper and roughly what kind of outlines are inside, which matters for where the font can be used.
.ttf
TrueType: quadratic outlines in a glyf table.
“Which table holds TrueType outlines?”
.otf
OpenType, often with CFF cubic outlines.
“What does CFF stand for?”
.woff
Web Open Font Format 1.0: sfnt tables compressed with zlib.
“How is WOFF compressed?”
.woff2
WOFF 2.0: Brotli compression and table transforms, much smaller.
“Which format is smallest?”
.ttc
A collection of several fonts sharing tables.
“What does a .ttc hold?”
The Tables That Matter
A font is a set of tables, each with a four-letter tag and its own job. These are the ones this inspector reads to build its report, and the ones to look at first when something about a font seems wrong. The check view lists every table in the file with its size.
name
Family, style, version, designer, foundry and licence text.
OS/2
Weight, width, embedding permissions, vendor and vertical metrics.
cmap
Which characters map to which glyphs.
GSUB and GPOS
Substitution and positioning features such as ligatures and kerning.
fvar
Variable font axes and named instances.
Embedding Permissions
Every font carries a set of embedding flags in its OS/2 table, called fsType, that tells software whether the font may travel inside a PDF, an app or a web page. They record the licence’s intent, so read the licence itself too, but software such as PDF exporters does obey them.
Installable
No restriction: the font may be embedded and installed on the reader’s system.
Restricted
The font must not be embedded at all; PDF exporters will fall back or refuse.
Preview and Print
Documents may embed it to view and print, but not to edit their text.
Editable
Embedded text may be edited, but the font can’t be installed permanently.
Font Checking Tips
Things to confirm before a font goes into a product, a website or a print job, where swapping it later is expensive. Each takes a minute with the views above, and together they answer most licensing and support questions.
Read the Licence
The name table often carries the licence and a link to it.
Check Embedding
Restricted fonts mustn’t be embedded in PDFs or apps.
Check Coverage
Make sure every language you need has its characters.
Prefer WOFF2 on the Web
It’s usually the smallest file for the same font.
Subset Carefully
Subsetting removes characters and sometimes features.
Registered Variable Axes
A variable font holds a range of styles in one file, described by axes in its fvar table. Five axes have registered lowercase tags that CSS maps to familiar properties, while foundries invent uppercase tags for anything else, such as the height of ascenders.
wght, Weight
From thin to black, usually somewhere between 100 and 900; CSS font-weight sets it.
wdth, Width
Condensed to expanded as a percentage of normal width; CSS font-stretch sets it.
slnt and ital, Slant and Italic
slnt leans the letters by degrees, while ital switches to true italic shapes.
opsz, Optical Size
Adjusts details for the point size, sturdier when small and finer when large.
When to Inspect a Font
Whenever you need facts about a font that its file name and a preview can’t give you. Font files often arrive renamed, re-exported or without their licence, and the tables inside are the most reliable record of what they are.
Web Font Setup
Find the axes and features to use in CSS.
Licence Questions
Read who made the font and under what licence.
Localisation
Check a font covers Greek, Cyrillic or Vietnamese.
Debugging Missing Glyphs
See which characters a font doesn’t have.
Font Delivery
Confirm a file isn’t damaged before shipping it.
Font File Pitfalls
Problems that show up only after a font is in use, and that a quick inspection catches first. Most are invisible in a type preview and only appear in a menu, a PDF export or a language you didn’t test.
Restricted Embedding
Some licences forbid embedding even if the file works.
Missing Characters
Text falls back to another font where glyphs are missing.
Edited Files
A file changed after building can fail checksum checks.
Wrong Style Names
Badly named styles group wrongly in font menus.
Partial Downloads
A cut-off file may install but render nothing.