diff --git a/src/lyapunov.c b/src/lyapunov.c
index e4c3df6..ced9ac3 100644
--- a/src/lyapunov.c
+++ b/src/lyapunov.c
@@ -136,8 +136,8 @@ int lyapunov(
       // average lyapunov
       for(i=0; i<MATSIZE; i++){
 	// exclude inf
-	if(! isinf(lyapunov[i])){
-	  lyapunov_avg[i]=lyapunov_avg[i]*prevtime/time+lyapunov[i]*(time-prevtime)/time;
+	if((! isinf(lyapunov[i])) && (time>starting_time)){
+	  lyapunov_avg[i]=lyapunov_avg[i]*(prevtime-starting_time)/(time-starting_time)+lyapunov[i]*(time-prevtime)/(time-starting_time);
 	}
       }