diff --git a/block/parallels.c b/block/parallels.c
index f9a3b999ea..7a8e8b05a9 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -476,8 +476,9 @@ static int parallels_create(const char *filename, QemuOpts *opts, Error **errp)
     memcpy(header.magic, HEADER_MAGIC2, sizeof(header.magic));
     header.version = cpu_to_le32(HEADER_VERSION);
     /* don't care much about geometry, it is not used on image level */
-    header.heads = cpu_to_le32(16);
-    header.cylinders = cpu_to_le32(total_size / BDRV_SECTOR_SIZE / 16 / 32);
+    header.heads = cpu_to_le32(HEADS_NUMBER);
+    header.cylinders = cpu_to_le32(total_size / BDRV_SECTOR_SIZE
+                                   / HEADS_NUMBER / SEC_IN_CYL);
     header.tracks = cpu_to_le32(cl_size >> BDRV_SECTOR_BITS);
     header.bat_entries = cpu_to_le32(bat_entries);
     header.nb_sectors = cpu_to_le64(DIV_ROUND_UP(total_size, BDRV_SECTOR_SIZE));
diff --git a/block/parallels.h b/block/parallels.h
index 71183c0c8e..4b044079ef 100644
--- a/block/parallels.h
+++ b/block/parallels.h
@@ -34,6 +34,8 @@
 #include "qemu/coroutine.h"
 #include "qemu/typedefs.h"
 
+#define HEADS_NUMBER 16
+#define SEC_IN_CYL 32
 #define DEFAULT_CLUSTER_SIZE 1048576        /* 1 MiB */
 
 /* always little-endian */