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GC content calculator

Measure GC content and base composition of a nucleotide sequence.

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GC content

Paste a sequence to calculate.

FormulaGC% = (G + C + S) ÷ (G + C + S + A + T + W) × 100

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About this tool

Calculate GC content as a percentage of assignable positions, along with a full base count. Ambiguous positions are reported separately rather than folded into the denominator, because a GC value computed over positions that could go either way is not a GC value.

Related tools

  • Reverse complement — Generate the reverse, complement or reverse complement of a sequence.
  • DNA translation — Translate a nucleotide sequence into protein in any reading frame.

Science last reviewed .