How to open .TTF files (TrueType fonts) on Android, Windows and Linux

You downloaded a font for a poster, a client sent their brand fonts, or a project folder is full of files like Inter-SemiBoldItalic.ttf. On a phone, tapping one often leads nowhere. And you’d like to know what the font is called and whether you may use it.

Folders has a font viewer for TTF and OTF files on Android, Windows and Linux. It shows the font in use, lets you type your own text in it, and lists the names, version and licence stored inside the file.

What is a .ttf file?

A .ttf file is a TrueType font. Apple developed TrueType and licensed it to Microsoft, and it became the standard font format of Windows. It describes each letter as an outline of curves, so text stays sharp at any size, with “hinting” instructions that help small text look crisp on screens.

OpenType, created by Microsoft and Adobe, extends TrueType. An OpenType font can hold TrueType outlines or PostScript-style outlines (called CFF), and adds typographic features: ligatures, small capitals, alternative letter shapes and support for many writing systems. The .otf extension usually means the PostScript kind; many .ttf files today are OpenType fonts with TrueType outlines.

Extension	What it is	Where you meet it
.ttf	TrueType font, or OpenType with TrueType outlines	Windows system fonts, Google Fonts downloads, fonts bundled with apps
.otf	OpenType font, usually with PostScript (CFF) outlines	Type foundries, design and print work

Inside, a font is a set of tables: the letter shapes, a map from characters to shapes, and a “name” table with the family, style, version, designer and licence, which is what Folders reads for its details.

How to open a .ttf file with Folders

On Android:

1. Install Folders from the download page and allow access to your files.
2. Find the font file, or search for its name, and tap it. It opens in the font viewer.
3. If it came by email or chat, tap the attachment and choose Open with → Folders.

Fonts often come zipped: a Google Fonts download is a ZIP with the fonts inside, sometimes in a static folder. Tap the ZIP in Folders, then a .ttf inside it, or use Extract all to keep the files.

On Windows and Linux:

1. Browse to the font in Folders and double-click it.
2. On Windows, you can also right-click it in File Explorer → Open with → Folders; the installer adds Folders to that menu for TTF and OTF files.

What you can do with it in Folders

• See the specimen: the font’s full name set in the font itself, a line of sample letters and numbers, and a badge saying TTF or OTF.
• Read the details stored in the font: family, style, full name, version, designer, manufacturer, copyright and licence, as far as the maker filled them in.
• Preview your own words. Type in Type to preview, and Folders shows the text at six sizes from 12 to 72, for judging body text and headlines.
• Look at the glyphs. The Glyphs grid shows common characters in the font: letters, digits, punctuation, symbols such as € £ © and °, and some accented and Greek letters.
• Share, rename or Compress to ZIP from the file browser, to send a set of fonts to someone.

Folders shows fonts; it doesn’t install or edit them. To use a font in other programs, install it with your system’s tools.

Other ways to open .ttf files

• Windows: double-click a font for Windows’ own font viewer with its Install button, or right-click it → Install or Install for all users.
• Linux: GNOME’s Fonts app or KDE’s font manager preview and install fonts; or copy them to ~/.local/share/fonts and run fc-cache -f.
• FontForge (free, Windows and Linux) inspects or edits every glyph.
• Android has no built-in way to install a font system-wide, though some phone makers’ theme apps can, and some apps let you add fonts of your own.

Problems opening a .ttf file?

• Folders says the file “may be damaged or not a TrueType/OpenType font”. The download may be incomplete, or the file is something else with the wrong extension. Download it again from the original source.
• The file ends in .woff or .woff2. Those are compressed web fonts for websites, not .ttf or .otf files. Most font sites offer a desktop download as well.
• The details are empty. Some fonts leave the name fields blank. The font itself still works.
• You installed it but an app doesn’t list it. Restart the app. On Linux, run fc-cache -f; on Windows, some older programs only see fonts installed for all users.

Questions people ask

How do I install a TTF font on Android? Stock Android doesn’t offer it. Check whether your phone maker’s theme app supports fonts, or add the font inside the app where you need it. Folders previews fonts but doesn’t install them.

TTF vs OTF: which is better? For everyday use, neither: both work on Windows, Linux and in most apps. OTF files more often carry advanced typographic features, and many type designers prefer PostScript outlines for print.

Is a TTF file safe? Fonts are data, but bugs in font software have been exploited through specially made fonts in the past. Get fonts from sources you trust and keep your system updated.

Can I use a free font for commercial work? Free to download doesn’t always mean free to use commercially. Check the licence in Folders’ font details, or the licence file that came with the font. Many Google Fonts use the SIL Open Font License, which allows commercial use.

Related guides: how to open SVG files and how to open Lottie animations, or browse all 382 file types Folders opens.