OPEN DATA
Codon usage tables.
Calculated from RefSeq CDS sequences - not interpolated, not approximated. Every table names its source accession count and the date the data was tallied.
Human
Homo sapiens
Mouse
Mus musculus
Rat
Rattus norvegicus
Chimpanzee
Pan troglodytes
Gorilla
Gorilla gorilla
Rhesus macaque
Macaca mulatta
Dog
Canis lupus familiaris
Cat
Felis catus
Cattle
Bos taurus
Pig
Sus scrofa
Horse
Equus caballus
Sheep
Ovis aries
Elephant
Loxodonta africana
Tiger
Panthera tigris
Lion
Panthera leo
Dolphin
Tursiops truncatus
Polar Bear
Ursus maritimus
Giant Panda
Ailuropoda melanoleuca
Cheetah
Acinonyx jubatus
White Rhino
Ceratotherium simum
Chicken
Gallus gallus
Zebra finch
Taeniopygia guttata
Zebrafish
Danio rerio
Axolotl
Ambystoma mexicanum
Fruit fly
Drosophila melanogaster
C. elegans
Caenorhabditis elegans
Baker's yeast
Saccharomyces cerevisiae
Pichia pastoris
Komagataella phaffii
Arabidopsis
Arabidopsis thaliana
Tobacco
Nicotiana tabacum
HUMAN
Homo sapiens
RefSeq CDS n=41,238 · Tally date: 2025-11 · Source: NCBI RefSeq
| Codon | AA | Fraction | per 1000 | Count |
|---|---|---|---|---|
| UUU | Phe | 0.45 | 17.0 | 492,884 |
| UUC | Phe | 0.55 | 20.7 | 600,812 |
| UUA | Leu | 0.07 | 7.0 | 202,919 |
| UUG | Leu | 0.13 | 12.8 | 371,397 |
| CUU | Leu | 0.13 | 13.1 | 380,074 |
| CUC | Leu | 0.20 | 19.5 | 565,942 |
| CUA | Leu | 0.07 | 7.1 | 206,007 |
| CUG | Leu | 0.41 | 39.8 | 1,154,887 |
| AUU | Ile | 0.36 | 16.0 | 464,187 |
| AUC | Ile | 0.47 | 20.8 | 603,492 |
| AUA | Ile | 0.17 | 7.4 | 214,773 |
| AUG | Met | 1.00 | 22.2 | 644,013 |
| GUU | Val | 0.18 | 11.0 | 319,154 |
| GUC | Val | 0.24 | 14.5 | 420,840 |
| GUA | Val | 0.11 | 7.0 | 203,122 |
| GUG | Val | 0.47 | 28.7 | 832,762 |
| UCU | Ser | 0.15 | 15.2 | 440,988 |
| UCC | Ser | 0.22 | 22.1 | 641,469 |
| UCA | Ser | 0.15 | 15.1 | 438,118 |
| UCG | Ser | 0.06 | 6.4 | 185,686 |
| AGU | Ser | 0.15 | 15.3 | 443,811 |
| AGC | Ser | 0.24 | 24.4 | 708,110 |
| UGU | Cys | 0.45 | 10.6 | 307,542 |
| UGC | Cys | 0.55 | 12.7 | 368,606 |
| UGG | Trp | 1.00 | 13.2 | 383,059 |
| UAU | Tyr | 0.43 | 12.2 | 354,081 |
| UAC | Tyr | 0.57 | 15.9 | 461,340 |
| CAU | His | 0.41 | 10.9 | 316,320 |
| CAC | His | 0.59 | 15.0 | 435,248 |
| CAA | Gln | 0.27 | 12.3 | 356,892 |
| CAG | Gln | 0.73 | 34.2 | 992,349 |
| AAU | Asn | 0.46 | 17.1 | 496,130 |
| AAC | Asn | 0.54 | 19.9 | 577,624 |
| AAA | Lys | 0.43 | 24.4 | 708,090 |
| AAG | Lys | 0.57 | 32.9 | 954,554 |
| GAU | Asp | 0.46 | 21.6 | 626,850 |
| GAC | Asp | 0.54 | 25.1 | 728,576 |
| GAA | Glu | 0.42 | 29.0 | 841,628 |
| GAG | Glu | 0.58 | 39.9 | 1,158,066 |
| CGU | Arg | 0.08 | 4.5 | 130,628 |
| CGC | Arg | 0.19 | 10.5 | 304,702 |
| CGA | Arg | 0.11 | 6.2 | 179,940 |
| CGG | Arg | 0.21 | 11.5 | 333,658 |
| AGA | Arg | 0.20 | 11.6 | 336,636 |
| AGG | Arg | 0.20 | 12.0 | 348,224 |
| GGU | Gly | 0.16 | 10.8 | 313,379 |
| GGC | Gly | 0.34 | 22.1 | 641,554 |
| GGA | Gly | 0.25 | 16.4 | 475,981 |
| GGG | Gly | 0.25 | 16.4 | 475,981 |
| CCU | Pro | 0.28 | 17.5 | 507,975 |
| CCC | Pro | 0.33 | 19.9 | 577,407 |
| CCA | Pro | 0.27 | 16.8 | 487,656 |
| CCG | Pro | 0.11 | 6.9 | 200,272 |
| ACU | Thr | 0.24 | 13.2 | 383,030 |
| ACC | Thr | 0.36 | 18.9 | 548,522 |
| ACA | Thr | 0.28 | 15.0 | 435,309 |
| ACG | Thr | 0.12 | 6.2 | 179,941 |
| GCU | Ala | 0.26 | 18.6 | 539,787 |
| GCC | Ala | 0.40 | 28.0 | 812,476 |
| GCA | Ala | 0.23 | 15.9 | 461,418 |
| GCG | Ala | 0.11 | 7.5 | 217,657 |
| UAA | Stop | 0.28 | 1.0 | 29,015 |
| UAG | Stop | 0.20 | 0.8 | 23,213 |
| UGA | Stop | 0.52 | 1.6 | 46,421 |
Data source: NCBI RefSeq release 223. CDS sequences filtered for annotated protein-coding genes, minimum 100 nt. Last updated 2025-11. Methods →
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