DNA to Protein Length Calculator

Why the math isn't simply dividing by 3

Each amino acid is encoded by a three-nucleotide codon, but the coding sequence includes one extra codon that doesn't translate into an amino acid: the stop codon marking translation's end - that codon has to be subtracted out to get the true protein length.

Worked example

For a 300 base pair coding sequence:

Total Codons = 300/3 = 100

Protein Length = 100 - 1 = 99 amino acids

This calculation assumes a straightforward coding sequence without introns (which would already have been removed via splicing to produce the mature mRNA coding sequence used here) and a single reading frame with no unusual features like frameshifting.