Can I control the GC content?

Yes — for DNA and RNA you can set a target GC fraction and bases are drawn to approximately match it.

What is this useful for?

Generating negative controls, test inputs for pipelines, placeholder sequences, and teaching examples.

Random DNA / RNA / Protein Sequence Generator

Generate random sequences with an optional GC target.

🔒 Runs entirely in your browser — nothing is uploaded

Generate random DNA, RNA or protein sequences of any length, with an optional target GC content for nucleotides. Random sequences make excellent negative controls, placeholder inputs for testing pipelines and parsers, and teaching examples.

Sequence type

Length

Target GC content

Random sequence

Click Generate

How to use the Random Sequence tool

1Choose DNA, RNA or protein and set the length you need.
2Optionally set a target GC fraction for nucleotide sequences.
3Generate and copy the sequence — regenerate for a fresh one anytime.

Frequently asked questions

Can I control the GC content?: Yes — for DNA and RNA you can set a target GC fraction and bases are drawn to approximately match it.
What is this useful for?: Generating negative controls, test inputs for pipelines, placeholder sequences, and teaching examples.

Related tools

Reverse Complement

Get the reverse, complement or reverse complement of a DNA/RNA sequence.

Sequence Formatter

Clean, case-convert, wrap, reverse and convert between DNA and RNA.

Translate DNA

Translate a nucleotide sequence to protein in any or all six reading frames.