diff --git a/src/os/win32/ngx_shmem.c b/src/os/win32/ngx_shmem.c
index 07a6714..5f3af8b 100644
--- a/src/os/win32/ngx_shmem.c
+++ b/src/os/win32/ngx_shmem.c
@@ -15,7 +15,7 @@
     u_char    *name;
     uint64_t   size;
 
-    name = ngx_alloc(shm->name.len + 2 + sizeof(NGX_INT32_LEN), shm->log);
+    name = ngx_alloc(shm->name.len + 2 + NGX_INT32_LEN, shm->log);
     if (name == NULL) {
         return NGX_ERROR;
     }