diff --git a/fslmeants.cc b/fslmeants.cc
index 27fd9dc635b14ea38c4bcda0b3bcfea62d1a6d15..a77724360037742a43fcbae62b442aa9e97e5fb8 100644
--- a/fslmeants.cc
+++ b/fslmeants.cc
@@ -178,7 +178,7 @@ int main(int argc,char *argv[])
     int nt = vin.tsize();
     int nvox = 1;
     if (showall.value()) {
-      nvox = MISCMATHS::round(mask.sum()+0.5);
+      nvox = MISCMATHS::round(mask.sum());
       nt += 3;
     }
     Matrix meants(nt,nvox);