Reverse complement
Tools
- Sequence stats
- Reverse complement
- FASTA/FASTQ format validator
- FASTQ → FASTA
- FASTA ID deduplicator
- DNA ↔ RNA converter
Computes the reverse complement of DNA or RNA sequences by reversing the sequence and applying the appropriate nucleotide complement mapping (IUPAC-aware).
About this tool
Compute reverse complements, complements, or reverse-only sequences for DNA or RNA. Accepts FASTA (multiple records) or a single raw sequence. Ambiguous IUPAC nucleotide codes are preserved and complemented (e.g. R↔Y, W↔W, N↔N). For background and worked examples of the reverse complement operation, see the reverse complement reference.
- ✓ No hidden transformations or guessing
- ✓ Input processed once and not stored
- ✓ FASTA headers preserved
Details
- Complement: replace each base with its pair (DNA A↔T, C↔G; RNA A↔U, C↔G).
- Reverse: read the sequence backwards (3′→5′) without changing bases.
- Reverse complement: apply complement, then reverse, so the result is reported 5′→3′.
- IUPAC: ambiguity codes (R,Y,S,W,K,M,B,D,H,V,N) are supported for nucleic acids.
- Validation: malformed FASTA fails loudly; no auto-fixing or hidden transformations.
- Case preservation: output uses the same letter case as the input.
- Primer and probe work: generate the reverse primer sequence from a target region.
- Orientation checks: confirm strand direction when comparing against a reference.
- Minus-strand features: interpret annotations reported on the opposite strand.
- Quick verification: sanity-check copied sequences and small fragments during analysis.
DNA and RNA are read and reported in the 5′→3′ direction, but nucleic acids are paired as antiparallel strands. When you have a sequence from one strand, the reverse complement gives you the sequence that would pair with it, expressed in the same 5′→3′ convention.
This tool provides a strict reverse-complement generator for FASTA inputs or a single raw sequence, with explicit DNA/RNA selection, IUPAC-aware base handling.
