FASTQ to CSV
Export FASTQ headers, sequences and original quality strings to CSV.
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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
- FASTQ sequence reads and quality (.fastq)
- FASTQ sequence reads and quality (.fq)
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 FASTQ 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.
- Four-line FASTQ records only, no wrapped sequences or quality. IUPAC nucleotide symbols and printable ASCII quality. Sequence/quality lengths and repeated plus-line headers must match. Inspection assumes Phred+33 explicitly; historical Phred+64 and Solexa scores are not detected.
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 fastq 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.
More scientific tools
- Inspect FASTQ reads and quality
Inspect FASTQ read lengths and explicit Phred+33 quality statistics in your browser.
- FASTQ to FASTA
Extract FASTQ read headers and sequences as FASTA, discarding quality scores.
- FASTQ to JSON
Export FASTQ headers, sequences and original quality strings to JSON.
- HDF5 dataset to JSON
Select one numeric HDF5 dataset and export its values locally.
- HDF5 dataset to CSV
Select one numeric HDF5 dataset and export its values locally.
- Inspect FASTA sequences
Summarize FASTA record lengths and sequence symbol counts locally.