What happens to a partial final codon?

Any 1 or 2 bases left after the last complete codon are reported as the remainder, not translated. Make sure your sequence starts in frame 1 (at the first base of a codon).

Does it optimise codons for an organism?

No. It reports the codon usage of the sequence you give it. It does not compare against a species’ codon-usage table or suggest an optimised sequence.

Codon usage calculator

Tabulate codon and amino-acid usage across a coding sequence read in frame 1, and translate it to protein. Trailing bases that don’t complete a codon are reported separately.

How it works

Formula

Read the sequence three bases at a time from position 1. Count how often each codon appears, translate each with the standard codon table (stops shown as *), and tally amino acids. Any leftover 1–2 bases are the remainder.

Worked example

ATG GCA AAA GCA GCA TAA translates to M-A-K-A-A-* (protein MAKAA*). GCA appears 3 times — the most-used codon — and there are no trailing bases.

When to use it

To check the codon composition of a gene or construct — spotting rare codons that may slow expression in a host, confirming a reading frame translates cleanly, or getting amino-acid counts.

Sensible defaults

The default ATGGCAAAAGCAGCATAA gives the protein MAKAA* with GCA used three times. Paste a CDS in frame 1 to profile it.

FAQ

What happens to a partial final codon?: Any 1 or 2 bases left after the last complete codon are reported as the remainder, not translated. Make sure your sequence starts in frame 1 (at the first base of a codon).
Does it optimise codons for an organism?: No. It reports the codon usage of the sequence you give it. It does not compare against a species’ codon-usage table or suggest an optimised sequence.