diff --git a/src/fix_langevin.cpp b/src/fix_langevin.cpp
index 7fb556639e..48f7a3c9ea 100644
--- a/src/fix_langevin.cpp
+++ b/src/fix_langevin.cpp
@@ -197,3 +197,14 @@ void FixLangevin::reset_target(double t_new)
 {
   t_start = t_stop = t_new;
 }
+
+/* ---------------------------------------------------------------------- */
+
+void FixLangevin::reset_dt()
+{
+  for (int i = 1; i <= atom->ntypes; i++) {
+    gfactor2[i] = sqrt(atom->mass[i]) * 
+      sqrt(24.0*force->boltz/t_period/update->dt/force->mvv2e) / force->ftm2v;
+    gfactor2[i] *= 1.0/sqrt(ratio[i]);
+  }
+}
diff --git a/src/fix_langevin.h b/src/fix_langevin.h
index 9b614e8823..8a8a89aeb8 100644
--- a/src/fix_langevin.h
+++ b/src/fix_langevin.h
@@ -28,6 +28,7 @@ class FixLangevin : public Fix {
   void post_force(int);
   void post_force_respa(int, int, int);
   void reset_target(double);
+  void reset_dt();
 
  private:
   double t_start,t_stop,t_period;