Biology

Codon Table Explorer

Explore all 64 standard-code codons. Search amino acids and switch between DNA and RNA notation.

The standard genetic code

64 codons · 20 amino acids · 3 stop signals

Find a codon or amino acid

Show stop codons only

Showing 64 of 64 codons

UUU

Phenylalanine

Phe

UUC

Phenylalanine

Phe

UUA

Leucine

Leu

UUG

Leucine

Leu

UCU

Serine

Ser

UCC

Serine

Ser

UCA

Serine

Ser

UCG

Serine

Ser

UAU

Tyrosine

Tyr

UAC

Tyrosine

Tyr

UAA

Stop

Stop · Termination

UAG

Stop

Stop · Termination

UGU

Cysteine

Cys

UGC

Cysteine

Cys

UGA

Stop

Stop · Termination

UGG

Tryptophan

Trp

CUU

Leucine

Leu

CUC

Leucine

Leu

CUA

Leucine

Leu

CUG

Leucine

Leu

CCU

Proline

Pro

CCC

Proline

Pro

CCA

Proline

Pro

CCG

Proline

Pro

CAU

Histidine

His

CAC

Histidine

His

CAA

Glutamine

Gln

CAG

Glutamine

Gln

CGU

Arginine

Arg

CGC

Arginine

Arg

CGA

Arginine

Arg

CGG

Arginine

Arg

AUU

Isoleucine

Ile

AUC

Isoleucine

Ile

AUA

Isoleucine

Ile

AUG

Methionine

Met · Canonical start

ACU

Threonine

Thr

ACC

Threonine

Thr

ACA

Threonine

Thr

ACG

Threonine

Thr

AAU

Asparagine

Asn

AAC

Asparagine

Asn

AAA

Lysine

Lys

AAG

Lysine

Lys

AGU

Serine

Ser

AGC

Serine

Ser

AGA

Arginine

Arg

AGG

Arginine

Arg

GUU

Valine

Val

GUC

Valine

Val

GUA

Valine

Val

GUG

Valine

Val

GCU

Alanine

Ala

GCC

Alanine

Ala

GCA

Alanine

Ala

GCG

Alanine

Ala

GAU

Aspartic acid

Asp

GAC

Aspartic acid

Asp

GAA

Glutamic acid

Glu

GAG

Glutamic acid

Glu

GGU

Glycine

Gly

GGC

Glycine

Gly

GGA

Glycine

Gly

GGG

Glycine

Gly

Read codons 5′→3′. Standard code (NCBI table 1); alternative codes are not included. A single-letter search matches the amino acid code exactly.

How to use

Choose DNA or RNA
Switch the table between T and U notation.
Search the code
Filter by a codon, amino acid name, or one- or three-letter code.
Compare assignments
Read standard amino acids, the canonical ATG/AUG start and stop signals.

Why ToolerWork?

Private by design

Sequence calculations run inside your browser.

Clear assumptions

Strand direction, code table and approximation limits are explained.

Related Tools

View All

Codon Lookup Tool

Look up a DNA or RNA codon to find its amino acid, abbreviation and stop-codon status.

DNA to Protein Translator

Translate DNA into amino acids in any of six reading frames using the standard genetic code.

ORF Finder

Find ATG-start open reading frames on both DNA strands, with coordinates and translated proteins.

Why use this tool?

Explore all 64 codons in one searchable reference.
Switch notation without changing amino acid assignments.
Download the current table as a tab-separated reference.

Method & assumptions

This chart contains all 64 triplets from NCBI standard genetic code table 1. The table encodes 20 standard amino acids and three stop signals. ATG/AUG is marked as the canonical start; alternative initiation contexts and genetic codes are outside this chart.

References: NCBI genetic codes

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Frequently asked questions

Why are there 64 codons?

Each of three positions can contain one of four bases, giving 4 × 4 × 4 = 64 triplets.

How many codons encode amino acids?

In the standard code, 61 encode amino acids and three are termination signals. Several codons can encode the same amino acid.

Can I search by a one-letter amino acid code?

Yes. A single-letter query matches the amino acid code exactly. For example, L finds the six leucine codons.

Does switching to RNA change the code?

No. The chart replaces T with U while keeping the same standard-code amino acid assignments.

Why might my organism use a different codon assignment?

Some organelles and organisms use alternative genetic codes. Check the relevant NCBI translation table before applying a standard chart to them.