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Triangle Circumradius from Sides Calculator

R = abc / (4 · area), area via Heron.

Compute the circumradius R of a triangle from its three side lengths a, b, c: R = abc / (4·area), where area is computed via Heron's formula. Reports area and inradius too.

Daniel Oh By Daniel Oh
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

s = (a+b+c)/2; area = √(s(s−a)(s−b)(s−c)); R = abc/(4·area); r_in = area / s.

In depth

Compute the circumradius R of a triangle from its three side lengths a, b, c: R = abc / (4·area), where area is computed via Heron's formula. Reports area and inradius too.