diff --git a/src/alloc.c b/src/alloc.c
index 621fb0db..be63f86a 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -443,7 +443,12 @@ mi_decl_allocator void* mi_calloc(size_t count, size_t size) mi_attr_noexcept {
 // Uninitialized `calloc`
 extern mi_decl_allocator void* mi_heap_mallocn(mi_heap_t* heap, size_t count, size_t size) mi_attr_noexcept {
   size_t total;
-  if (mi_mul_overflow(count,size,&total)) return NULL;
+  if (count==1) {
+    total = size;
+  }
+  else if (mi_mul_overflow(count, size, &total)) {
+    return NULL;
+  }
   return mi_heap_malloc(heap, total);
 }