Windows
Compatible applications
Quick Facts
Basic information about this file format
Extension
.FASTA
File Type
FASTA Sequence File
Category
Data
Best first step
Use compatible software
Quick Summary
A practical overview of the .fasta file format
The FASTA format is a text-based format for representing either nucleotide sequences or amino acid (protein) sequences, in which nucleotides or amino acids are represented using single-letter codes. The format also allows for sequence names and comments to precede the sequences. Originally develope…
File extension
.FASTA
File type
FASTA Sequence File
Category
Data
Recommended action
Open with a trusted compatible app
How to open a .fasta file
Start with a trusted app that supports this format
- Check the file extension carefully and confirm that the file name really ends with .fasta.
- Use software that supports this file type. If one app does not work, try another compatible program for the same platform.
- Update the application if the file was created by a newer version of the software.
- Scan files from unknown sources before opening them, especially documents, archives, scripts, installers, and executable files.
What is a .fasta file?
File extension details and usage information
The FASTA format is a text-based format for representing either nucleotide sequences or amino acid (protein) sequences, in which nucleotides or amino acids are represented using single-letter codes. The format also allows for sequence names and comments to precede the sequences. Originally developed for the FASTA software package, it has since become a near-universal standard in the field of bioinformatics and computational biology. A FASTA file typically begins with a single-line description, followed by lines of sequence data. The description line is distinguished from the sequence data by a greater-than symbol ('>') in the first column. The word immediately following the '>' symbol is the unique identifier of the sequence, while the remainder of the line provides additional metadata. Because FASTA files are stored in plain text, they are easily human-readable and can be manipulated using basic text editors or command-line tools. However, specialized bioinformatics software is generally used to process these files for tasks such as sequence alignment, homology searching, and genome assembly. The format's simplicity and flexibility have ensured its continued relevance despite the emergence of more complex formats like FASTQ, which includes quality scores.
Software Compatibility
Programs that may open or work with .fasta files
macOS
Compatible applications
Linux
Compatible applications
Mobile
Mobile applications
Can .fasta files be converted?
Options for saving or exporting this file to another format
In many cases, a .fasta file can be converted by opening it in compatible software and using an option such as Save As, Export, or Convert. The available output formats depend on the file type and the application used.
- Use the original software that created the file when possible.
- Check whether the application supports exporting to common formats.
- Be careful with online converters when working with private, business, or sensitive files.
- If conversion fails, the file may be corrupted, incomplete, encrypted, or not actually a .fasta file.
Why can't I open a .fasta file?
Common reasons this file type may not open correctly
Wrong software
The file may require a specific program that supports the .fasta format.
Incorrect extension
The file extension may have been renamed manually, even though the actual file format is different.
Corrupted file
The file may be incomplete, damaged during download, or transferred incorrectly.
Outdated app
Your software may need to be updated before it can open newer versions of this file format.
Frequently Asked Questions
Common questions about .fasta files
To open a .fasta file, use software that supports this file format.
- Notepad++
- SnapGene
- CLC Genomics Workbench
- BioEdit
- MEGA (Molecular Evolutionary Genetics Analysis)
Open the file in compatible software and look for options such as Save As, Export, or Convert. If no export option is available, the file may require a specialized converter or the original application that created it.
- Verify that the file extension is correct.
- Install or update compatible software.
- Try another application that supports this format.
- Check whether the file is corrupted, incomplete, or encrypted.
A file extension alone does not guarantee whether a file is safe or unsafe. Only open files from trusted sources, scan unknown files before opening them, and be especially careful with executable, script, archive, and document files.
File safety tips
Use caution with unknown files
Only open files from trusted sources. Before opening a .fasta file, scan it with antivirus software, verify that the file extension is expected, and avoid running unknown executable, installer, macro-enabled document, or script files.