BCFNU File

What are BCFNU files and how to open them

Are you having problems opening a BCFNU file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BCFNU files.

What is a BCFNU file?

A .BCFNU file is a Nintendo 3DS Bitmap Font Format file.

The Nintendo 3DS Bitmap Font Format stores bitmap font data used for rendering characters and text on the 3DS. It is used both for system fonts and for fonts inside games and applications. The format includes metadata about the font, texture sheets containing the glyph images, spacing metrics for each glyph, and mapping from character codes to glyph indices. It allows precise control over how characters are laid out, how wide each glyph is, where it sits relative to a baseline, and what encoding is used.

This font format is produced within Nintendo's toolbox (part of the NW4C library) during game development or by the system itself for default fonts. Software that reads the format parses the data in the font to render text onscreen using the texture atlas and the metrics, matching characters to glyphs, placing them with correct spacing.

Each file begins with a header that identifies it as a 3DS bitmap font, followed by a FINF ("Font INFormation") section with properties such as font type, default character widths, encoding, and offsets to other sections. There are sections named TGLP ("TeXturE Glyph Pages") for the texture atlas, CWDH ("Character Widths") for glyph metric data, and CMAP ("Character MAP") for mapping characters to glyph indices. FINF's header also stores values such as line feed, ascent height, width/height of glyph cells, and reserved bytes.

The file format uses identifiable signatures: the file starts with ASCII bytes "CFNU", one of the section headers contains "FINF" at offset 20, and the file contains strings "CMAP", "CWDH", "TGLP" inside it.

How to open BCFNU files

Important: Different programs may use files with the BCFNU file extension for different purposes, so unless you are sure which format your BCFNU file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 23, 2026

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