What is the FNT file format?
.fnt is a legacy binary font file format used by early Windows operating systems. .fnt files store raster (bitmap) or stroke (vector plotter) glyphs and their metadata, and are typically found in system directories used for storing fonts. In Windows distributions, .fnt files carry the hidden attribute by default and are rarely distributed as standalone files - they are embedded as resources inside .FON files, which are Windows NE or PE executables acting as font resource libraries.
Each .fnt file encodes glyphs for exactly one typeface at one point size. A complete font family therefore requires multiple .fnt files (or a single .fon container holding multiple resources). The format supports only 1-bit monochrome bitmaps - no grayscale or anti-aliasing. Windows 3.x shipped system fonts such as 8514fix.fon and vgasys.fon as .fon containers bundling multiple .fnt resources.
The format defines three versions identified by a byte at offset 1 of the file header: version 1 (Windows 1.x), version 2 (Windows 2.x), and version 3 (Windows 3.x), which added face name and device name pointer fields to the fixed 148-byte header.
FNT is a system font format, but many more universal formats have superseded it. TrueType (.ttf, introduced in 1991) and OpenType (.otf, 1996) are scalable outline formats that replaced .fnt for all new content. FontForge can read and convert .fnt files for preservation purposes.
Security & safety
RISK: LOWFNT files are passive binary data with no executable code. They pose no security risk when opened with a font tool.
Format details
in a nutshell- Radiance Renderer Font - Radiance (lighting simulation software) uses .fnt for its own simple bitmap font format, unrelated to Windows GDI.
- Various game engine bitmap fonts - Many retro and indie game engines use .fnt for custom bitmap font atlases (e.g. AngelCode BMFont format), unrelated to Windows GDI.
Programs that open FNT files
Windows2 apps
FontForge
Open-source File > Open, select the .fnt file. FontForge can display glyphs and export to TTF, OTF, or BDF. 
Microsoft Windows (built-in, limited)
Built-in Windows can install .fnt files by right-click > Install, but they appear only in legacy GDI apps; not displayed in the modern Fonts panel. 
macOS1 app
Linux1 app
FontForge
Open-source fontforge -lang=ff -c 'Open($1);Generate($1:r + ".ttf")' font.fnt - or open GUI. Technical details
deep spec| Encoding | Binary |
| Byte order | Little-endian |
| Version identifier | Byte at offset 1: 0x01 = version 1 (Windows 1.x), 0x02 = version 2 (Windows 2.x), 0x03 = version 3 (Windows 3.x) |
| Header size | 148 bytes (versions 2 and 3); contains family name, weight, width, height, first/last character codes, and copyright string |
| Glyph types | Raster (1-bit monochrome bitmap) or stroke (vector plotter definition); no color, grayscale, or anti-aliasing support |
| Color depth | 1 bpp (monochrome only) for raster glyphs |
| Scope per file | One typeface at one point size per .fnt file; a full font family requires separate files for each size and style |
| Distribution method | Typically embedded inside .fon container files (Windows NE/PE executables); standalone .fnt files are uncommon |
| Compression | None - uncompressed bitmap or stroke data |
| Typical file size | 2 KB - 200 KB (scales with number of glyphs and point size encoded) |
| MIME type | application/octet-stream (no official registration; font/fnt used informally) |
| Associated OS | Windows 1.0 through Windows 3.x natively; present in later Windows versions for backward compatibility only |
| Superseded by | TrueType (.ttf, 1991) and OpenType (.otf, 1996) - scalable outline font formats that replaced FNT for all new development |
| Released | 1983, with Windows 1.0 pre-release development; shipped with Windows 1.0 (1985) |
| Latest version | Version 3 (Windows 3.x, 1990); no updates since |
| Open standard | Yes · royalty-free |
| Specification | docs.microsoft.com |
FNT conversions
Community Q&A
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