Transcribe DNA sequences to RNA by replacing thymine with uracil. Learn more
Input
How to convert DNA to RNA
Paste a DNA sequence or upload a FASTA-style text file, then select Convert. The DNA to RNA converter changes every thymine (T) to uracil (U), retains the other nucleotide and ambiguity codes, and returns a copyable, downloadable .fasta file. It is useful when the input is the coding strand, where the RNA sequence has the same bases as DNA except for T to U.
For a plain sequence, the converter creates a FASTA header and, with the default header setting, adds rna_ before it:
Input
ATGCTTACGA
Output
>rna_Sequence
AUGCUUACGAFASTA input is processed record by record. This example uses Preserve original case and No wrapping (single line) so the case behavior is visible:
Input
>reference_fragment
ATGCTTACGA
>mixed_case
aTgCtt
Output
>rna_reference_fragment
AUGCUUACGA
>rna_mixed_case
aUgCuuThe conversion is a character substitution, not a strand-complement operation. If the supplied DNA is a template strand rather than a coding strand, make a reverse complement first, then replace T with U.
Input
| Input | What the converter accepts |
|---|---|
| DNA sequence input | One pasted DNA sequence, plain text containing multiple FASTA records, or an uploaded .txt, .fasta, .fa, .fas, or .seq file. Uploaded files can be up to 50 MB. Plain sequences receive the default >Sequence header before header formatting is applied. |
| Sequence characters | With validation enabled, A, T, U, C, G, the IUPAC ambiguity codes R, Y, S, W, N, K, M, B, D, H, and V, plus . and -. Whitespace within a sequence is removed. An input U is accepted but reported as an RNA character in DNA input. |
Comment lines beginning with # and empty lines are ignored. For a regular FASTA record, put the header on its own line, beginning with >, followed by one or more sequence lines.
Settings
| Setting | Behavior |
|---|---|
Output case | Select UPPERCASE (AUCG) (default), lowercase (aucg), or Preserve original case. Uppercase and lowercase change sequence lines only, not FASTA headers. Preserve original case keeps the capitalization of each input residue while converting T to U. |
Line wrapping | Select 80 characters per line (standard) (default), 60 characters per line, or No wrapping (single line). The setting applies to every output sequence. |
Validate input sequences | Enabled by default. Each record containing characters outside the accepted set is skipped and reported in the warnings. DNA input that already contains U is still converted, but produces a warning that U is an RNA character. Turn this off only when retaining nonstandard sequence characters is intentional. |
Add suffix to headers | Enabled by default. For compatibility with the existing setting name, this option actually adds rna_ immediately after > in every FASTA header, such as >sample becoming >rna_sample. Turn it off to retain the original header exactly. |
Results
| Result | Contents |
|---|---|
| Preview | The converted sequences in FASTA format. Each record has a header, followed by RNA sequence lines using the selected case and wrapping. |
| Downloadable FASTA file | The same converted FASTA content. Pasted input downloads as converted.fasta; an uploaded file uses its original basename with a .fasta extension. |
| Conversion metadata | The result records the number of processed sequences, total input sequence length after whitespace removal, and the dna-to-rna direction. Warnings identify skipped records or DNA records that contain U. |
What does DNA to RNA conversion represent?
DNA and RNA use largely the same alphabet. DNA uses thymine, while RNA uses uracil, so a coding-strand DNA sequence ATGC corresponds to RNA AUGC. Ambiguity symbols describe uncertain bases and remain unchanged, as do alignment gaps (- and .).
In a cell, transcription is performed by an RNA polymerase reading the DNA template strand. This converter does not model promoters, strand orientation, splicing, or RNA processing. It only produces the nucleotide notation change needed when a DNA coding-strand sequence should be represented as RNA. To reverse the notation change, use the RNA to DNA converter.
Which sequence tool should I use?
| Goal | Tool to use | Why |
|---|---|---|
Replace T with U in a coding-strand DNA sequence | DNA to RNA converter | Produces RNA-formatted FASTA while retaining headers, ambiguity codes, and optional wrapping. |
Replace U with T in an RNA sequence | RNA to DNA converter | Reverses this conversion for RNA-formatted input. |
| Obtain the opposite DNA strand before representing it as RNA | Reverse complement | Complements bases and reverses sequence order, which this converter does not do. |
| Translate a coding sequence to amino acids | DNA to protein | Converts codons into a protein sequence rather than changing nucleotide notation. |
| Predict base pairing or secondary structure for RNA | RNAfold | Uses an RNA sequence to predict a secondary-structure ensemble. |
FAQ
Does DNA to RNA conversion complement the DNA sequence?
No. It replaces T with U and leaves the sequence order and other characters unchanged. Use reverse complement first if the sequence is a template strand and the required result is its RNA complement.
Can I convert multiple DNA sequences to RNA at once?
Yes. Paste or upload multiple FASTA records. The converter processes each valid record independently and returns them together in one FASTA file.
Why does my output header start with rna_?
Add suffix to headers is enabled by default, and its current behavior is to prefix the header identifier with rna_. Disable the setting when the input headers must remain unchanged.
Can DNA input include IUPAC ambiguity codes?
Yes. The converter accepts standard ambiguity codes, including N, R, Y, K, and M, and keeps them unchanged. It only replaces T with U.
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