diff --git a/src/navier-stokes.c b/src/navier-stokes.c
index 24b4508..531398d 100644
--- a/src/navier-stokes.c
+++ b/src/navier-stokes.c
@@ -99,6 +99,9 @@ int energy(
   // copy initial condition
   copy_u(u, u0, K1, K2);
 
+  // init running average
+  avg=0;
+
   // iterate
   for(t=0;t<nsteps;t++){
     ins_step(u, K1, K2, N1, N2, nu, delta, L, g, fft1, fft2, ifft, tmp1, tmp2, tmp3);
@@ -111,8 +114,13 @@ int energy(
 	}
       }
 
-      fprintf(stderr,"%d % .8e % .8e\n",t,t*delta, energy);
-      printf("%8d % .15e % .15e\n",t,t*delta,energy);
+      // running average
+      if(t>0){
+	avg=avg-(avg-energy)/t;
+      }
+
+      fprintf(stderr,"%d % .8e % .8e % .8e\n",t,t*delta, energy, avg);
+      printf("%8d % .15e % .15e % .15e\n",t,t*delta,energy,avg);
     }
   }