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 That means you can safely paste unpublished or sensitive research sequences without worrying about where the data goes.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
BioOnSun Blog
Experiments often raise small questions that manuals and papers never quite answer. The BioOnSun blog covers practical, bench-ready tips and notes on interpreting your results — check it out.