DNA to mRNA Converter
Paste a DNA sequence and this tool transcribes it into messenger RNA by swapping thymine for uracil. Tell it whether you entered the coding strand or the template strand, since the template needs to be complemented first. Alongside the mRNA it also shows the complementary DNA strand, base for base, so you can check your pairing.
How to transcribe DNA to mRNA
- Type or paste a DNA sequence into the DNA sequence box using only A, C, G and T. Spaces and line breaks are ignored and lowercase is accepted.
- Under Strand provided, pick Coding strand if your sequence already reads like the mRNA (only T to U changes).
- Pick Template strand instead if you entered the strand the cell reads, so the tool complements it before the T to U swap.
- Read the mRNA result in the output box and click Copy to grab it.
- Check the Complementary DNA strand shown below to confirm the A-T and G-C pairing.
Examples
Coding strand: only T becomes U
ATGC, coding strand
AUGC
Template strand: complement first, then T to U
TACG, template strand
AUGC
A longer coding strand
GGATCCGT, coding strand
GGAUCCGU
Frequently asked questions
What does the coding versus template setting change?
On coding strand the tool leaves your bases in place and only turns each T into a U, because the coding (sense) strand already matches the mRNA. On template strand it first builds the complement (A to T, G to C) and then applies T to U, since the template (antisense) strand is what an RNA polymerase actually reads.
How is the transcription actually computed?
For the coding strand the result is your sequence with every T replaced by U. For the template strand the tool complements each base first (A pairs to U, T to A, G to C, C to G) then reports that as the mRNA. No reversal is applied, so the output lines up position by position with your input.
What is the complementary DNA strand shown below the result?
It is the base-for-base DNA complement of whatever you typed, using A-T and G-C pairing, not reversed. It is handy for double checking base pairing, but note it is DNA (still uses T) while the mRNA box above it uses U.
Which characters are allowed in the sequence?
Only the four DNA bases A, C, G and T, in upper or lower case. Whitespace is stripped automatically. Anything else, such as N, U or a digit, is rejected and the tool lists the exact invalid characters it found.
Does it handle uracil or RNA input?
No. The input must be DNA, so a U counts as an invalid base. If you already have RNA and want the reverse, this tool is not the right direction; transcribe from the DNA that produced it instead.
Is there a length limit on the sequence?
There is no fixed cap. The transcription is a simple character-by-character pass that runs in your browser, so the practical limit is your device memory. Even long sequences update almost instantly as you type.
Does this tool translate mRNA into a protein?
No. It stops at the mRNA. To read the mRNA in triplets and get the amino acid chain, use a codon translator, which maps each three-base codon to its amino acid.
Does it account for introns, splicing or a promoter?
No. This is a direct base-level transcription with no biology beyond the pairing rules. It does not remove introns, add a 5' cap or poly-A tail, or find start and stop signals, so treat it as a teaching and quick-conversion aid rather than a model of the full cellular process.
Is my sequence uploaded anywhere?
No. Everything runs locally in your browser and nothing is sent to a server, so any research or study sequence stays on your device.
Learn more
- Coding strand vs template strand in transcription
Why the two DNA strands give different transcription steps, how base pairing drives the mRNA, and which strand to pick in this tool.
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