Codon Chart
Look up one codon or scan all 64 Standard Code mappings in RNA or DNA notation.
Standard Code: NCBI translation table 1. Alternative mitochondrial and organellar codes can differ.
Lookup result
Showing all 64 Standard Code codons in RNA notation.
Standard Code chart
RNA (U) · 64 codons| Codon | Amino acid | 3-letter | 1-letter | Signal |
|---|---|---|---|---|
| UUU | Phenylalanine | Phe | F | — |
| UUC | Phenylalanine | Phe | F | — |
| UUA | Leucine | Leu | L | — |
| UUG | Leucine | Leu | L | — |
| UCU | Serine | Ser | S | — |
| UCC | Serine | Ser | S | — |
| UCA | Serine | Ser | S | — |
| UCG | Serine | Ser | S | — |
| UAU | Tyrosine | Tyr | Y | — |
| UAC | Tyrosine | Tyr | Y | — |
| UAA | Stop | — | — | Stop |
| UAG | Stop | — | — | Stop |
| UGU | Cysteine | Cys | C | — |
| UGC | Cysteine | Cys | C | — |
| UGA | Stop | — | — | Stop |
| UGG | Tryptophan | Trp | W | — |
| CUU | Leucine | Leu | L | — |
| CUC | Leucine | Leu | L | — |
| CUA | Leucine | Leu | L | — |
| CUG | Leucine | Leu | L | — |
| CCU | Proline | Pro | P | — |
| CCC | Proline | Pro | P | — |
| CCA | Proline | Pro | P | — |
| CCG | Proline | Pro | P | — |
| CAU | Histidine | His | H | — |
| CAC | Histidine | His | H | — |
| CAA | Glutamine | Gln | Q | — |
| CAG | Glutamine | Gln | Q | — |
| CGU | Arginine | Arg | R | — |
| CGC | Arginine | Arg | R | — |
| CGA | Arginine | Arg | R | — |
| CGG | Arginine | Arg | R | — |
| AUU | Isoleucine | Ile | I | — |
| AUC | Isoleucine | Ile | I | — |
| AUA | Isoleucine | Ile | I | — |
| AUG | Methionine | Met | M | Common start |
| ACU | Threonine | Thr | T | — |
| ACC | Threonine | Thr | T | — |
| ACA | Threonine | Thr | T | — |
| ACG | Threonine | Thr | T | — |
| AAU | Asparagine | Asn | N | — |
| AAC | Asparagine | Asn | N | — |
| AAA | Lysine | Lys | K | — |
| AAG | Lysine | Lys | K | — |
| AGU | Serine | Ser | S | — |
| AGC | Serine | Ser | S | — |
| AGA | Arginine | Arg | R | — |
| AGG | Arginine | Arg | R | — |
| GUU | Valine | Val | V | — |
| GUC | Valine | Val | V | — |
| GUA | Valine | Val | V | — |
| GUG | Valine | Val | V | — |
| GCU | Alanine | Ala | A | — |
| GCC | Alanine | Ala | A | — |
| GCA | Alanine | Ala | A | — |
| GCG | Alanine | Ala | A | — |
| GAU | Aspartic acid | Asp | D | — |
| GAC | Aspartic acid | Asp | D | — |
| GAA | Glutamic acid | Glu | E | — |
| GAG | Glutamic acid | Glu | E | — |
| GGU | Glycine | Gly | G | — |
| GGC | Glycine | Gly | G | — |
| GGA | Glycine | Gly | G | — |
| GGG | Glycine | Gly | G | — |
Private by design: your lookup and selected notation stay in this page. They are not put in the URL, saved, sent to a lookup server, or included in analytics.
How to read this codon chart
Read a codon as one three-base unit, then find its amino-acid assignment. The default table uses RNA letters A, C, G and U. DNA mode shows the corresponding coding-strand letters with T in place of U. For example, RNA AUG and DNA ATG both map to Methionine (Met, M).
Start and stop signals
AUG encodes Methionine and is commonly used as a start codon. That does not mean every AUG starts translation: initiation depends on biological context, and other genetic codes can use different initiation rules. In the Standard Code, UAA, UAG and UGA are stop signals; DNA mode shows TAA, TAG and TGA.
Exact codon and amino-acid lookup
Enter one codon, a full amino-acid name, its three-letter abbreviation, or its one-letter symbol. Matching is token based rather than substring based. Searching for Leucine, Leu or L returns its six codons and does not include Isoleucine. The complete chart remains visible below the lookup result.
Standard Code scope and exceptions
This page implements NCBI translation table 1 only. The Standard Code is widely used, but mitochondrial, organellar and other alternative codes exist. Confirm the correct code for specialized biological work. This reference does not translate sequences, select reading frames, find open reading frames, compare codon usage or frequency, optimize expression, interpret mutations, predict proteins, or provide medical guidance.
Privacy and method
The 64 mappings are built into the page from the cited NCBI Standard Code. Lookups run locally in your browser. Input is not saved, added to the URL, sent to a lookup service, or included in analytics. This page has no account, download, quiz or genetic-sequence upload.
Frequently asked questions
What does a codon chart show?
A codon chart maps each three-base RNA or DNA codon in a selected genetic code to an amino acid or stop signal. This page shows the NCBI Standard Code, translation table 1.
Is a codon chart read as RNA or DNA?
Codon charts are commonly written as mRNA codons with U. Choose DNA on this page to see the corresponding coding-strand triplets with T. The amino-acid assignments stay the same.
What are the three stop codons?
In the Standard Code, the RNA stop codons are UAA, UAG and UGA. Their DNA equivalents are TAA, TAG and TGA.
Is AUG always a start codon?
AUG encodes Methionine and is commonly used to initiate translation, but initiation depends on biological context and the selected genetic code. Alternative codes and initiation rules exist.
Does this chart translate a DNA or RNA sequence?
No. It looks up one codon or one exact amino-acid name or symbol. It does not choose a reading frame, find an open reading frame, or translate a sequence.