diff --git a/src/immersedBoundary/immersedBoundary/include/immersedBoundaryCompressibleCourantNo.H b/src/immersedBoundary/immersedBoundary/include/immersedBoundaryCompressibleCourantNo.H
new file mode 100644
index 000000000..058736d01
--- /dev/null
+++ b/src/immersedBoundary/immersedBoundary/include/immersedBoundaryCompressibleCourantNo.H
@@ -0,0 +1,79 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | foam-extend: Open Source CFD
+   \\    /   O peration     | Version:     4.1
+    \\  /    A nd           | Web:         http://www.foam-extend.org
+     \\/     M anipulation  | For copyright notice see file Copyright
+-------------------------------------------------------------------------------
+License
+    This file is part of foam-extend.
+
+    foam-extend is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the
+    Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    foam-extend is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with foam-extend.  If not, see <http://www.gnu.org/licenses/>.
+
+Global
+    compressibleCourantNo
+
+Description
+    Calculates and outputs the mean and maximum Courant Numbers for 
+    compressible flow with immersed boundary correction.
+
+Author
+    Hrvoje Jasak, Wikki Ltd.  All rights reserved
+
+\*---------------------------------------------------------------------------*/
+
+scalar CoNum = 0.0;
+scalar meanCoNum = 0.0;
+scalar velMag = 0.0;
+
+// HR 26.06.18: A parallel run has at least two cells and therefore at least
+// one internal face in the global mesh. It may be a processor boundary, but
+// this is captured by max(mag(phi)).
+// Old formulation hangs on parallel cases where one partition is degenerated
+// to a single cell.
+if (mesh.nInternalFaces() || Pstream::parRun())
+{
+    surfaceScalarField phiOverRho = sGamma*mag(phi)/fvc::interpolate(rho);
+
+    surfaceScalarField SfUfbyDelta =
+        mesh.surfaceInterpolation::deltaCoeffs()*phiOverRho;
+
+    CoNum = max(SfUfbyDelta/mesh.magSf()).value()*runTime.deltaT().value();
+
+    meanCoNum = (sum(SfUfbyDelta)/sum(mesh.magSf())).value()*
+        runTime.deltaT().value();
+
+    velMag = max(phiOverRho/mesh.magSf()).value();
+}
+else
+{
+    // Single cell mesh: Co is still defined; use cell formulation
+
+    const scalar deltaT = runTime.deltaT().value();
+
+    const scalar deltaX = Foam::cbrt(mesh.V()[0]);
+
+    velMag = mag(U[0]);
+
+    CoNum = velMag*deltaT/deltaX;
+
+    meanCoNum = CoNum;
+}
+
+Info<< "Courant Number mean: " << meanCoNum
+    << " max: " << CoNum
+    << " velocity magnitude: " << velMag
+    << endl;
+
+// ************************************************************************* //