About the DNA to Protein Translator
DNA to Protein Translator reads a DNA or RNA sequence three bases at a time and writes the amino acids they code for, using the standard genetic code. Choose to translate from the first ATG start codon to the first stop, or to translate a whole reading frame (frame 1, 2 or 3), and choose the forward strand or the reverse complement. The protein is shown in the one-letter code with the three-letter version below it, and a star marks a stop codon. You can paste plain letters or a FASTA sequence, and U is accepted as T.
Updated October 2026
How to use the DNA to Protein Translator
- 1Paste your DNA or RNA sequence, plain or in FASTA format.
- 2Choose from the first ATG to a stop, or a whole reading frame.
- 3Choose the forward strand or the reverse complement.
- 4Pick frame 1, 2 or 3 if you translate a whole frame.
- 5Copy the one-letter or three-letter protein.
From gene to protein
A gene is a stretch of DNA that is first copied into messenger RNA and then read by the ribosome. The code is read in triplets, so a sequence of 300 bases can make a protein of up to 100 amino acids. The start codon sets the reading frame, which is why a single inserted or missing base can change every amino acid after it.
Using the two modes
The first mode is the quick answer for a coding sequence: it finds the first ATG and translates until the first stop. The second mode shows a whole frame, including stops, which is useful when you want to look at all possible frames or when your sequence is a fragment that does not start with ATG.
- Complete gene: use the first ATG mode
- A fragment: translate frames 1, 2 and 3 and look for the longest run without stops
- The gene may be on the other strand: switch to the reverse complement
Reading the result
Methionine (M) at the start and a star at the end mean a complete open reading frame. Many stars in a row suggest the wrong frame or strand. A protein that never reaches a stop codon before the sequence ends is marked as incomplete.
Related tools
Get the opposite strand with the Reverse Complement Calculator and the base balance with the GC Content Calculator. The Binary Translator and Morse Code Translator show other ways to encode information.
Features
- Standard genetic code, all 64 codons
- First open reading frame or any of three frames
- Forward or reverse complement strand
- One-letter and three-letter output
- FASTA and U accepted
- Private: nothing is uploaded
Frequently asked questions
How is DNA translated into protein?
Cells read mRNA in groups of three bases called codons. Each codon stands for one amino acid or a stop signal, and the amino acids are joined into a protein. This tool does the same from a DNA sequence.
What is the start codon?
ATG (AUG in RNA), which codes for methionine (M) and begins most proteins.
What are the stop codons?
TAA, TAG and TGA (UAA, UAG, UGA in RNA). They end the protein and appear as a star in the result.
What is a reading frame?
One of three ways to group the bases into codons, starting at the first, second or third base. Only one frame usually carries the real gene.
Why try the reverse complement?
Genes can lie on either strand of DNA. If you find nothing useful on the forward strand, translate the reverse complement.
Does it work for mitochondria or bacteria?
It uses the standard code. Mitochondria and some organisms use small variations, for example TGA coding for tryptophan in human mitochondria.
What is the three-letter code?
Abbreviations such as Met, Ala and Gly. The one-letter code M, A and G is shorter and common in databases.
Is my sequence uploaded?
No. It is translated in your browser.