GB File

What are GB files and how to open them

Are you having problems opening a GB 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 GB files.

What is a GB file?

GB files have multiple uses, and Nintendo Game Boy ROM is one of them. Read more about the other uses further down the page.

Nintendo Game Boy ROM File

Files that contain the .gb file extension usually contain a ROM image of a game from a Game Boy game cartridge. The Game Boy is a portable gaming device introduced by Nintendo in 1989.

The GB file holds an exact copy of the data from the game cartridge of an associated Game Boy game. The GB file is stored in a read-only ROM format. This file can be used to play the associated game on a Mac or PC. However, to play the game, the user must have the proper emulation software installed on their hard drive.

How to open GB files

We have identified two GB openers that are compatible with this specific type of GB file.

Programs that open Nintendo Game Boy ROM files

Last updated: August 6, 2026

All known file formats using extension .GB

While Nintendo Game Boy ROM File is a popular type of GB-file, we know of 2 different uses of the .GB file extension. Different software may use files with the same extension for different types of data.

GenBank Gene Sequence Record

A GenBank Gene Sequence Record (file extension .GB, also .GBK, .GENBANK, .GP) is a plain-text file format used by the National Center for Biotechnology Information (NCBI) to store a DNA or RNA sequence along with detailed biological annotations. It represents a single sequence entry (or multiple entries in one file) and includes metadata such as the sequence's source organism, publication references, and functional information about genes, coding regions, RNA, and other biological features. This format is used for sharing and archiving publicly submitted nucleotide sequences.

Files in this format are created by sequence submission pipelines, genome databases, or researchers depositing sequence data into NCBI's GenBank database or other collaborating databases (e.g. EMBL, DDBJ). Users typically read them with bioinformatics tools for sequence retrieval, analysis, visualization, or conversion into other formats (for instance, FASTA or GFF). Each record starts with identifying information (locus name, length, molecule type, etc.), followed by a "FEATURES" section where annotated genomic features are described, and concludes with the "ORIGIN" section which carries the full nucleotide sequence.

Technically, a file begins with a line that starts with "LOCUS", followed later by the sections labelled "FEATURES" and "ORIGIN". An entry ends with two slashes ("//"). The nucleotide sequence under ORIGIN is shown in the 5′-to-3′ directional string, formatted in groups of ten bases per block, sixty bases per line.

GB opener for Windows

We have identified one GB opener that is compatible with this specific type of GB file.

Various apps that use files with this extension

These apps are known to open certain types of GB files. Remember, different programs may use GB files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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