Use this free online reverse complement tool to generate reverse complements, complements, reversed sequences, or cleaned DNA from plain-text, FASTA, or GenBank input, with IUPAC ambiguity-code support.
Useful Checks
This is useful when sequence orientation must be fixed before primer design, restriction-site checks, or ORF translation.
Copy the cleaned sequence or reverse complement into downstream tools such as Primer Designer, Primer Binding Checker, Restriction Site Analyzer, ORF and Protein Translator, or Codon Optimizer.
Minimum Inputs Needed
DNA sequence.
Optional Settings
Line wrap
Controls how many bases are shown per line in the output.
Output format
Use Plain sequence for sequence-only output. Use FASTA when you need labeled FASTA records.
Upload sequence file (optional)
Use this instead of pasting if you already have a sequence file.
How To Use
Paste or upload the DNA sequence.
Choose wrapping and output format.
Click Generate.
Copy the output you need.
Understanding The Results
Reverse complement reverses the sequence and complements each base.
Complement changes each base but keeps the original order.
Reverse sequence reverses the order but does not complement bases.
Cleaned input shows the parsed sequence in uppercase.
Live input stats and results show length, exact bases, ambiguous bases, and GC%.
Accepted Input Formats
Raw DNA sequence.
FASTA. Headers are ignored. Multiple records are concatenated into one sequence rather than processed separately.
GenBank text with an ORIGIN sequence section. Feature annotations, including ori/origin-of-replication annotations, are ignored.
IUPAC ambiguity codes are supported.
Accepted uploads include .txt, .fa, .fasta, .fna, .ffn, .seq, .gb, .gbk, and .genbank. .dna / SnapGene binary files are not supported.
Assumptions And Limitations
This is a DNA tool. It does not treat RNA as a separate mode.
GenBank annotations are ignored.
GC% is calculated from A/T/G/C bases only.
The browser tool accepts sequence files smaller than 2 MB and parsed sequences up to 100,000 bp.
Example
Paste a primer or DNA fragment, click Generate, and copy the reverse complement when you need the opposite strand.
Use note: These tools are for research and educational planning. Check important calculations and sequence designs before ordering reagents or running experiments.