diff --git a/Geo/STensor3.h b/Geo/STensor3.h
index d286062dd3c9fbbd5e5e06c2f6e2a5834b53f497..92243848ed60894e46bf6f625b817b03e05403e6 100644
--- a/Geo/STensor3.h
+++ b/Geo/STensor3.h
@@ -305,6 +305,12 @@ class STensor3 {
     return prod;
   }
 
+  double determinant() const{
+    fullMatrix<double> m(3,3);
+    getMat(m);
+    double det = m.determinant();
+    return det;
+  };
   void print(const char *) const;
 };