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GC Content of DNA Calculator

Percent G + C bases and estimated melting temperature.

Compute the GC content (percent of bases that are G or C) of a DNA strand from its base counts, and estimate the melting temperature using the Wallace rule for short oligos and the GC-formula for longer ones.

Priya Venkatesan By Priya Venkatesan
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

%GC = (G + C) / (A + T + G + C) · 100; Tm (Wallace) = 2(A+T) + 4(G+C).

In depth

Compute the GC content (percent of bases that are G or C) of a DNA strand from its base counts, and estimate the melting temperature using the Wallace rule for short oligos and the GC-formula for longer ones.