DNA and mRNA to protein translator
Paste a DNA or mRNA sequence and translate it codon by codon with the standard genetic code. Pick one of the three forward or three reverse reading frames, or see all six at once; stop codons are shown as *.
Runs in your browser: nothing you enter is sent anywhere.
How to use
- Paste a DNA or mRNA sequence (FASTA headers, spaces and numbers are skipped).
- Choose the reading frame. Frame +1 starts at the first base; pick All six frames to compare them.
- Choose one-letter or three-letter amino acid codes and copy the protein.
How it works
The sequence is cut into codons of three bases from the start of the chosen frame, and each codon is looked up in the standard genetic code: ATG → M (Met), GCC → A (Ala), TAA → * (stop) and so on. Translation does not stop at a stop codon — the whole frame is shown, so you can see where the stops are. One or two bases left over at the end are not translated. For reverse frames the reverse complement is translated.
Worked example
The sample sequence ATG GCC ATT GTA ATG GGC CGC TGA AAG GGT GCC CGA TAG gives in frame +1
MAIVMGRKGAR
— 13 codons: Met-Ala-Ile-Val-Met-Gly-Arg, a stop (TGA), then Lys-Gly-Ala-Arg and a final stop (TAG).
Tips
- To find a gene, look for the frame with an ATG followed by a long stretch without *.
- In all-frames mode each frame is a FASTA record (>+1 … >-3), easy to paste into other tools.
- The translation starts exactly at the chosen frame, not at the first ATG; trim the sequence if you want to start at a particular codon.
Frequently asked questions
What is a reading frame?
Codons are read three bases at a time, so a sequence can be cut into codons in three ways on each strand. Frame +1 starts at the first base, +2 at the second, +3 at the third; frames −1 to −3 do the same on the reverse complement. Usually only one frame gives a long protein without stop codons — the open reading frame.
Which genetic code is used?
The standard code (NCBI table 1), used by the nuclear genes of most organisms. Mitochondria and some microbes use variant codes in which, for example, TGA codes for tryptophan instead of stop; this tool does not apply those.
What do * and X mean in the protein?
* is a stop codon (TAA, TAG or TGA). X is a codon with an ambiguous base such as N, which cannot be translated with certainty. In three-letter mode they are Ter and Xaa.
Do I need to convert mRNA to DNA first?
No. U is read as T, so AUG and ATG both give methionine. Spaces, line breaks, digits and FASTA headers are ignored.