FASTA / FASTQ Sequence Tools
Free online bioinformatics tools for DNA and RNA sequences: format conversion, GC content analysis, reverse complement and six-frame translation.
FASTA to FASTQ
Convert FASTA sequences to FASTQ by adding placeholder quality scores.
FASTQ to FASTA
Strip quality scores from sequencing reads and keep only headers and sequences.
GC Content & Stats
Sequence length, GC content, AT content, N count, GC skew and AT skew per record.
Reverse Complement
Get the reverse complement of DNA sequences, with IUPAC ambiguity codes supported.
DNA to Protein
Translate nucleotide sequences into amino acids in all three reading frames.
FASTA and FASTQ formats
FASTA is the simplest sequence format: a header line starting with
> followed by the sequence. FASTQ adds a per-base quality
score, using four lines per record — header, sequence, a + separator line,
and a quality string of the same length encoded as ASCII characters.
When to use which
- Use FASTA for reference genomes, protein sequences and alignments.
- Use FASTQ for raw sequencing reads — the quality scores are needed for trimming and error correction.
Notes on this toolset
- Everything runs server-side; nothing is stored or logged.
- All tools accept multi-record files and preserve record order.
- IUPAC ambiguity codes (N, R, Y, K, M, S, W, B, D, H, V) are handled by the reverse complement tool.