Codon ChartHow to read a codon chart
A codon is a group of three nucleotides read in the 5′ to 3′ direction. In an RNA codon chart the bases are U, C, A and G. DNA uses T in place of U. Choose the first two bases to find a card, then read the complete three-base codon. For example, AUG encodes methionine in the standard code, while UUU encodes phenylalanine. Selecting a codon shows its full amino-acid name and abbreviations beside the chart.
The standard genetic code has 64 possible codons. Of these, 61 specify amino acids and three signal termination: UAA, UAG and UGA. Several codons can specify the same amino acid. This redundancy does not mean that every possible base substitution leaves the protein unchanged.
Choose the code for your sequence
The default is NCBI translation table 1, the standard code. Mitochondria and some organisms use different assignments. Select another table before interpreting a sequence from one of those systems. The chart follows the NCBI genetic-code tables, including context-dependent assignments. A codon listed as a possible start is not automatically an initiation site in a real sequence.
Switch to the codon wheel for a center-outward view or the amino acid chart to compare names and abbreviations. To translate an entire sequence, use DNA to protein; it lets you inspect all six reading frames.
Print or reuse your chart
Download SVG creates a vector chart that stays sharp when resized. Print uses a simplified page layout; your browser can also save that page as a PDF. The selected RNA or DNA alphabet and genetic code carry through to the SVG. Color groups make the chart easier to scan, while text labels keep every assignment readable without relying on color.