diff --git a/src/CCubes.c b/src/CCubes.c
index 248fe1a..9805d5a 100755
--- a/src/CCubes.c
+++ b/src/CCubes.c
@@ -233,7 +233,13 @@ SEXP CCubes(SEXP tt) {
 	int n_tasks_batch = 512;
         for (int task = 0; task < n_tasks; task+=n_tasks_batch) {
 		/* adjust if batch size is larger than total job size */
-		int current_batch = n_tasks < n_tasks_batch ? n_tasks : n_tasks_batch;
+		int current_batch = n_tasks_batch;
+		/* single batch */
+		if (n_tasks < n_tasks_batch)
+			current_batch = n_tasks;
+		/* last batch */
+		if (n_tasks - task < n_tasks_batch)
+			current_batch = n_tasks - task;
 
 		log_debug("ccubes", "Tasks %d - %d out of %d",
 		    task, task + current_batch - 1, n_tasks);