diff --git a/src/object.c b/src/object.c
index 234e11f8..10209a6c 100644
--- a/src/object.c
+++ b/src/object.c
@@ -834,7 +834,9 @@ size_t objectComputeSize(robj *o, size_t sample_size) {
             d = ((zset*)o->ptr)->dict;
             zskiplist *zsl = ((zset*)o->ptr)->zsl;
             zskiplistNode *znode = zsl->header->level[0].forward;
-            asize = sizeof(*o)+sizeof(zset)+(sizeof(struct dictEntry*)*dictSlots(d));
+            asize = sizeof(*o)+sizeof(zset)+sizeof(zskiplist)+sizeof(dict)+
+                    (sizeof(struct dictEntry*)*dictSlots(d))+
+                    zmalloc_size(zsl->header);
             while(znode != NULL && samples < sample_size) {
                 elesize += sdsAllocSize(znode->ele);
                 elesize += sizeof(struct dictEntry) + zmalloc_size(znode);