Font File Inspector & Glyph Viewer

A font file holds far more than the shapes of letters. It stores its names, designer and licence notes, vertical metrics, the characters it supports, layout rules for ligatures and kerning and, for variable fonts, the design axes. When you receive a file called Final-Regular.ttf, or need to know why a character shows in a fallback font, the answer is inside. This inspector opens the file in your browser and presents the useful parts in plain language.

Names and licence

The Names panel shows the full name, PostScript name, version, designer, manufacturer, copyright, licence text and licence URL, whichever the font maker stored. A dash means the field is empty. The licence field contains only what the designer typed: an empty field does not mean the font is free, and a short field may link to a longer document. If the font records an embedding permission, the panel adds it as a line starting “Embedding flags”. These are requests addressed to applications that embed fonts in documents; the actual licence always has priority.

A worked example

Press Sample to load Geist, a variable font shipped as a 28.7 KB WOFF2. The report reads family Geist, style Regular, 288 glyphs and WOFF2. The names panel shows full name Geist Regular, PostScript name Geist-Regular, version 1.800, the copyright of the Geist Project Authors and the licence URL https://openfontlicense.org; the licence text itself is not stored. The metrics show 1000 units per em, an ascender of 1005, a descender of -295, a line gap of 0, an x-height of 530, a cap height of 710, weight class 400 (Regular) and TrueType outlines. One variable axis is listed: wght, Weight, minimum 100, default 400, maximum 900.

Metrics and axes

The ascender, descender and line gap set the font’s natural line spacing: here the line box is 1005 + 295 + 0 = 1300 units, which is 1.3 times the font size. X-height and cap height tell you how large lower-case and capital letters look at a given size, so two fonts with the same size but different x-heights do not look equal. The axes table lists each variation axis with its tag, name, range and default, and any named instances such as Light or Bold.

Layout features

GSUB lists substitution features and GPOS positioning features by four-letter tag with a plain-English name where one is known. Geist’s GSUB list includes liga (standard ligatures), frac (fractions), tnum (tabular figures) and pnum (proportional figures), and its GPOS has kern, mark and mkmk. Turn them on in CSS with font-feature-settings or the matching font-variant properties. The table list, 20 tables for this font, includes fvar and gvar, which mark a variable font.

Character coverage

The 225 characters in the sample are grouped by block: Basic Latin 95 of 96, Latin-1 Supplement 95 of 96, Latin Extended-A 4 of 128, General Punctuation 15 of 112, Currency Symbols 1 of 48, Arrows 2 of 112 and Mathematical Operators 1 of 256. Choose a block to see its characters. Type your own text in the preview and the page lists characters with no glyph, so you can see whether a language is supported before you commit to a font.

Edge cases

Fonts with a very large character set show only the first 240 glyph cells of the chosen block. A font that the browser cannot load as a webfont still shows its data but not a live preview, with a notice. Some fonts leave the x-height or cap height unset, shown as a dash. Metrics stored in different tables can disagree, which is why the same font can space lines slightly differently on different operating systems.

Limits

The inspector reports what is in the file and does not judge quality, check for errors or tell you what you may do with the font. Nothing is uploaded.

Related tools

• Font Subsetter trims a font to the characters you need.
• TTF to WOFF2 Converter repackages the file for the web.
• Variable Font Tester explores the axes shown in the table.
• Line Height Calculator turns metrics into comfortable spacing.