DNA to mRNA Converter
Paste a DNA sequence (A, T, C, G only) and specify whether it's the coding (sense) strand or the template (antisense) strand to generate the corresponding mRNA sequence.
Last updated: September 22, 2026
Frequently asked questions
What's the difference between the coding strand and the template strand?
The coding (sense) strand has the same sequence as the mRNA that gets transcribed (except T instead of U), while the template (antisense) strand is the strand RNA polymerase actually reads to synthesize mRNA, and is complementary to both the coding strand and the resulting mRNA. This calculator requires you to specify which one you're providing, since the correct mRNA output depends entirely on that choice.
What happens if I select the wrong strand type for my sequence?
You'll get an mRNA sequence that's the complement of the correct answer rather than the correct one itself, since coding-strand and template-strand inputs are processed completely differently. If your result looks unexpected, double-check which strand your sequence actually represents before troubleshooting further.
Why does the calculator reject certain characters?
Only the four standard DNA bases - A, T, C, and G - are accepted, since the tool is built around a straightforward, defensible transcription rule for standard sequences. Ambiguity codes (like N, R, Y, etc.) and any other characters aren't supported and will be flagged as invalid so you can correct the input rather than getting a silently incorrect result.
Does this tool predict the resulting protein?
No - this is a DNA-to-mRNA sequence transcription utility only. It doesn't model translation, reading frames, start/stop codons, or resulting amino acid sequences, and it doesn't account for real biological processes like splicing, promoters, or post-transcriptional modification.
Can I paste a sequence with line breaks or spaces?
Yes - the calculator strips whitespace (spaces, tabs, line breaks) automatically before processing, so you can paste a sequence formatted across multiple lines and it will be normalized into one continuous sequence before conversion.
Why does converting a coding strand just swap T for U?
Because mRNA is synthesized as the complement of the template strand, which makes it identical in sequence to the coding strand (aside from using U instead of T) - so for a coding-strand input, generating the mRNA is as simple as that single substitution, without needing to compute a complement.