FASTA to CSV
Export FASTA identifiers, descriptions and sequence strings to CSV.
Drop your files here
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Multiple files welcome · processed one at a time
Select a tool to see its supported formats and conversion limits. Large files may exceed your browser’s memory.
Before processing large files
On phones and tablets, start with files under 20 MiB and keep this tab in the foreground. Video, OCR and 3D operations can use several times the input size in memory. Desktop browsers generally have more room, but the 128 MiB job limit is not a guarantee that every file will fit. Smaller batches reduce memory pressure.
Supported input formats
- FASTA biological sequences (.fasta)
- FASTA biological sequences (.fa)
- FASTA nucleotide sequences (.fna)
- FASTA coding nucleotide sequences (.ffn)
- FASTA amino acid sequences (.faa)
- FASTA noncoding RNA sequences (.frn)
Output format
Comma-separated values (.csv)
Support applies to this conversion direction. Check the limits below for features that may change or be discarded.
Compare all supported formats and conversion limits →How to use FASTA to CSV
- Add your supported file using the chooser or drop zone.
- Review the settings and conversion limits before processing.
- Select Convert files, then download the result.
What to expect
- UTF-8, uncompressed files only, maximum 64 MiB, 100,000 records and 20 million sequence symbols. No alignment or biological interpretation.
- Accepts IUPAC nucleotide and protein letters, gaps and stop symbols. Sequence case is preserved. Symbol counts are literal; alphabet and DNA/protein identity are not inferred. Semicolon comments are omitted.
Engine: Local sequence parser. The engine may need a first-use download. Your file stays in this browser session.Check conversion engines and offline requirements.
About this conversion
Is fasta to csv free?
Yes. This tool runs on your device without an account or a conversion fee.
Are files uploaded during conversion?
File processing happens locally in your browser. Engines may download their code on first use; your input files are not sent to a conversion server. Read how file privacy works.
What if conversion fails?
Check that the file matches a supported input, review the engine’s limitations and try a smaller representative file. If the engine cannot load, check its engine assets and browser requirements. The app reports failures without switching to a remote converter.
Continue with your output
These tools accept this tool’s output format. Each step has its own settings and fidelity limits.
- Numeric data to HDF5
Create a single selected HDF5 dataset from a numeric matrix or an exported JSON envelope.
- Numeric CSV to Matrix Market
Turn a headerless numeric CSV matrix into sparse Matrix Market coordinate data, omitting zero entries.
- CSV to JSON
Convert CSV locally with an explicit structured-data mapping.
- CSV to TSV
Convert CSV locally with an explicit structured-data mapping.
- CSV to YAML
Convert CSV locally with an explicit structured-data mapping.
- CSV to XML
Convert CSV locally with an explicit structured-data mapping.
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- HDF5 dataset to CSV
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- Inspect FASTQ reads and quality
Inspect FASTQ read lengths and explicit Phred+33 quality statistics in your browser.