DNA GC Content Calculator

Paste a DNA sequence (A, C, G, T). We’ll calculate GC%, AT%, length, and nucleotide counts.

DNA sequence (A, C, G, T)

We ignore spaces/new lines and convert to uppercase.

Tip

GC% can influence melting temperature and stability of DNA (simplified rule).

This tool checks only base letters.

GC content

—

Sequence length

—

Valid bases counted

Base counts

—

Only A, C, G, T are counted. If your sequence includes other symbols (N, gaps, etc.), they are flagged as invalid.