FASTQ → FASTA Conversion

Convert FASTQ sequencing reads into FASTA format by removing quality scores

Supported formats: FASTQ, FQ and compressed FASTQ files (.fastq.gz, .fq.gz) (Maximum size: 500 MB per file)

FASTQ → FASTA Conversion

Function

FASTQ → FASTA Conversion transforms sequencing reads from FASTQ format into FASTA format by removing quality score information while preserving read identifiers and nucleotide sequences.

Input Format

  • FASTQ files (.fastq, .fq)
  • Compressed FASTQ files (.fastq.gz, .fq.gz)
  • Multiple input files are supported.

Output Format

  • Standard FASTA format (.fasta)
  • Sequence identifiers begin with >
  • Quality scores are removed.

Applications

  • Preparing sequences for BLAST searches.
  • Input generation for tools that only accept FASTA format.
  • Sequence-only analyses.
  • Building reference databases.
  • Reducing storage requirements by removing quality scores.

Example Conversion

@Read_001
ATGCATGCATGC
+
IIIIIIIIIIII

↓

>Read_001
ATGCATGCATGC

SeqKit Example

seqkit fq2fa input.fastq \
-o output.fasta

AWK Example

awk 'NR%4==1 {
print ">"substr($0,2)
}
NR%4==2 {
print
}' input.fastq > output.fasta

Compressed FASTQ Example

zcat input.fastq.gz | \
awk 'NR%4==1 {
print ">"substr($0,2)
}
NR%4==2 {
print
}' > output.fasta

Suggested Reading

Important Notes:
  • Quality scores are permanently removed during conversion.
  • Keep the original FASTQ files if quality information may be required later.
  • Multiple FASTQ files can be converted in a single run.
  • Output files retain sequence identifiers from the original FASTQ.