DNA to mRNA Converter

How to use this calculator

1. Paste up to 3,000 nucleotide letters. Lowercase, spaces, and line breaks are accepted; remove sequence headings, numbering, and punctuation.
2. Choose coding DNA, template DNA, or RNA, and specify the direction in which your input is written. Direction describes the pasted text, not the desired output.
3. Select the reading frame after RNA is oriented 5′ to 3′. Choose whether to stop at the first termination codon or display every complete codon.
4. Compare the aligned sequences, protein letters, codon mapping, and status. Check skipped and incomplete bases before interpreting the translation.

Formula and method

For the assumptions behind these results, read the explanation below. You can also explore DNA Copy Number and DNA Concentration.

Choose the right DNA strand

Coding and template name the two strands relative to a particular transcript. The RNA sequence matches the coding strand when both are written 5′ to 3′, except that RNA uses uracil, U, where DNA uses thymine, T. The template strand provides complementary bases and runs in the opposite direction.

For a template written 3′ to 5′, apply A→U, T→A, C→G, and G→C directly across the line. If the template is written 5′ to 3′, reverse its order as well as complementing it. A direction change alone reverses a sequence; it does not exchange its bases.

Read the selected frame

A codon contains three RNA bases. Frame 1 groups bases 1–3, 4–6, and so on. Frame 2 begins at base 2, while frame 3 begins at base 3. These positions always refer to the normalized RNA output, even when the pasted input runs in the opposite direction.

The converter looks up each complete codon in the standard genetic code, NCBI table 1. It starts exactly where you choose, without finding a start codon or predicting an open reading frame. For example, UUG is displayed as leucine in this direct mapping; the tool does not apply special initiation rules.

Interpret stops and incomplete codons

UAA, UAG, and UGA are termination codons in this code. The default mode ends translation at the first one and excludes it from the amino-acid string. The codon mapping still shows the encountered stop. Show-all mode uses an asterisk for each stop and continues the lookup so that different frames can be inspected.

Letters beyond a stop in show-all mode are not a prediction of one uninterrupted protein. One or two bases left at the end cannot form a complete codon and are reported separately. Leading bases skipped by the frame are counted separately too. Full-sequence GC content includes those bases and any sequence after a stop.

Sequence conversion has biological limits

This tool treats the supplied letters as one continuous sequence. It does not remove introns, infer exon boundaries, add a cap or poly(A) tail, or simulate RNA editing. For an intended protein prediction, use an appropriately annotated coding sequence or processed transcript and confirm the reading frame.

An RNA input produces corresponding DNA sequence equivalents. Those letters do not reconstruct the original genomic region: processing may have removed or changed sequence information. Mitochondria and some organisms use different genetic codes, so their translations may differ. The tool also cannot determine expression, protein folding, activity, or whether a sequence is a real gene.