Genetic Code Table
Genetic code table — look up any codon (e.g. AUG) for its amino acid, or an amino acid for its codons, and view the full standard code table. Amino acid names in your curriculum's language. Curriculum-aligned.
Genetic Code Table
Type an mRNA codon (e.g. AUG; DNA T is read as U) to get its amino acid, or type an amino acid (e.g. Met or Methionine) to list its codons.
- Curriculum
- English (global) — Cambridge International + IB
- Built against
- Cambridge IGCSE Biology 0610 + IB / A-Level (2023–2025) — Protein Synthesis
- Unit system
- SI primary; US/imperial readout below
- First published
- 2 Jun 2026
- Last updated
- 2 Jun 2026
View authoritative scientific sources
- NCBI — standard genetic code (translation table 1)
- IUPAC-IUBMB — amino acid nomenclature
- Campbell Biology, 12th edition — protein synthesis
- Genetic code — Encyclopædia Britannica
⚠️ Educational use only — see full disclaimer
EDUCATIONAL USE DISCLAIMER
This calculator is provided for educational and reference purposes only. It is not a substitute for instruction from a qualified teacher, your prescribed textbook, or your school's official curriculum materials.
When preparing for examinations, always cross-check our calculations and notation against your current syllabus and your teacher's guidance. Syllabus conventions and accepted notation vary between curricula and may change between examination years.
If you believe any calculation, notation, or curriculum reference in this tool is inaccurate, please let us know via the feedback button. We review feedback promptly and update tools when verified corrections are needed.
RECATOOLS accepts no liability for academic, examination, professional, or research outcomes arising from use of this tool.
How to Use the Genetic Code Table
Pick your curriculum
Use the curriculum pills above to match your syllabus (Cambridge, SEAB, SPM, SBMPTN, 高考, 學測 or HKDSE). Amino acid names and the whole page follow your selection.
Look up a codon or amino acid
Enter a codon like AUG, or an amino acid like Met. The search box works both ways.
Read the result
For a codon we show the amino acid, its three-letter code and whether it is a start or stop codon.
Use the full table
The standard code table below lists all 64 codons arranged by first, second and third base.
The Genetic Code, in Your Curriculum's Words
The Genetic Code (codon → amino acid)
Example: During translation the ribosome reads mRNA three bases at a time. The start codon AUG codes for methionine and begins protein synthesis.
Codons UAA, UAG and UGA are stop codons — they code for no amino acid and end the chain.
AUG → Met (Methionine), start codon; UAA → Stop
The genetic code is the set of rules that translates three-base sequences (codons) in mRNA into amino acids during protein synthesis. There are 64 possible codons (4³), coding for the 20 standard amino acids plus stop signals. Because 64 codons code for only 20 amino acids, most amino acids are coded by more than one codon — a property called degeneracy.
This table works both ways: look up a codon for its amino acid, or an amino acid for all its codons. The three-letter and one-letter codes are international standards, but amino acid full names differ by language — including in Chinese, where the mainland uses the 氨酸 ending and Taiwan/Hong Kong use 胺酸. All data stays in your browser; nothing is uploaded.
The genetic code is nearly universal: the same codon codes for the same amino acid in bacteria, pea plants and humans alike.
10 Facts About the Genetic Code
The genetic code reads mRNA in three-base codons.
There are 64 codons (4³) coding for 20 amino acids.
AUG is the start codon and codes for methionine.
Three stop codons: UAA, UAG, UGA.
Most amino acids are coded by more than one codon (degeneracy).
The code is nearly universal across all life.
The three-letter codes (Met, Phe) are an international standard.
mRNA uses U (uracil) in place of DNA's T.
Each codon pairs with one tRNA anticodon.
This table runs in your browser — no data is uploaded.
Frequently Asked Questions
- A codon is a sequence of three nucleotide bases in mRNA that codes for one particular amino acid or a stop signal. Because there are four bases (U, C, A, G), there are 4³ = 64 possible codons, coding for the 20 standard amino acids plus three stop signals.
- Type an mRNA codon like AUG to get its amino acid, or type an amino acid like Met (or its full name) to list every codon that codes for it. If you enter a DNA sequence with T, we read it as U automatically.
- AUG is the start codon — it codes for methionine and marks where translation begins. UAA, UAG and UGA are stop codons; they code for no amino acid and tell the ribosome to end the polypeptide chain.
- Because 64 codons code for only 20 amino acids, most amino acids are coded by two to six codons. This property is called degeneracy or redundancy, and it helps reduce the impact of certain mutations.
- The genetic code is the same worldwide. What changes is the amino acid names and terminology; for example mainland China writes names with the 氨酸 ending (e.g. 甘氨酸) while Taiwan and Hong Kong use 胺酸 (甘胺酸). The three-letter codes such as Gly stay the same.
- This table uses mRNA codons, which contain uracil (U). If you have a template or coding DNA sequence, convert T to U first — or just type it with T and the tool converts it for you.
- Almost. This standard code (translation table 1) is used by nearly all organisms, but there are a few small exceptions, for example in mitochondria, where a handful of codons code for different amino acids.
- The Tool Information block lists the exact syllabus for your selected curriculum (e.g. SEAB A-Level Biology 9744 or SPM Biologi 4551). It is a study aid, not a substitute for your official syllabus or teacher.
- Completely free, no account or usage limit. It runs entirely in your browser and collects no data.
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