Bioinformatics tools
for research and learning
BioOnSun is a free collection of online tools for researchers, students, and hobbyist biologists working with DNA and RNA sequences. Your input never leaves your browser — everything is computed locally.
Available Tools
⇄Reverse Complement
Compute the reverse complement of a DNA/RNA sequence. Supports IUPAC ambiguity codes, FASTA format, and mixed case.
%GC Content Calculator
Calculate GC content, base composition, and GC skew, with a sliding-window chart.
▲DNA → Protein Translator
Translate DNA/RNA into protein across all 6 reading frames, with 18 genetic code tables.
✎FASTA Cleanup Tool
Automatically fix line breaks, whitespace, and headers into tidy FASTA.
≡Sequence Alignment
Align two DNA/RNA/protein sequences to see percent identity and exactly where they differ. Supports both global and local alignment.
Why BioOnSun exists
Working with sequences means constantly doing small, repetitive tasks — like reversing a sequence and converting it to its complement. Many existing tools are cluttered with ads, require sign-up, or don't work well on mobile. BioOnSun started as a project to fix that small annoyance.
Every calculation runs directly in your browser using JavaScript — nothing is sent to a server. That means you can safely paste unpublished or sensitive research sequences without worrying about where the data goes.
Who is this for?
- Researchers who need a quick reverse complement while designing primers or experiments
- Students working through molecular biology or bioinformatics coursework
- Hobbyists working with cloning, PCR primer design, and similar tasks
- Anyone who wants to work with sequences without installing any software