diff --git a/copyparty/__main__.py b/copyparty/__main__.py
index e0a46e79..e55c681a 100644
--- a/copyparty/__main__.py
+++ b/copyparty/__main__.py
@@ -1794,6 +1794,7 @@ def add_db_general(ap, hcores):
     ap2.add_argument("--no-idx", metavar="PTN", type=u, default=noidx, help="regex: disable indexing of matching absolute-filesystem-paths during e2ds folder scan (must be specified as one big regex, not multiple times) (volflag=noidx)")
     ap2.add_argument("--no-dirsz", action="store_true", help="do not show total recursive size of folders in listings, show inode size instead; slightly faster (volflag=nodirsz)")
     ap2.add_argument("--re-dirsz", action="store_true", help="if the directory-sizes in the UI are bonkers, use this along with \033[33m-e2dsa\033[0m to rebuild the index from scratch")
+    ap2.add_argument("--deep-dirsz", action="store_true", help="show correct sizes for child volumes in parent listings (possible drain on performance)")
     ap2.add_argument("--no-dhash", action="store_true", help="disable rescan acceleration; do full database integrity check -- makes the db ~5%% smaller and bootup/rescans 3~10x slower")
     ap2.add_argument("--re-dhash", action="store_true", help="force a cache rebuild on startup; enable this once if it gets out of sync (should never be necessary)")
     ap2.add_argument("--no-forget", action="store_true", help="never forget indexed files, even when deleted from disk -- makes it impossible to ever upload the same file twice -- only useful for offloading uploads to a cloud service or something (volflag=noforget)")
diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index 8c74664b..d764a873 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -7375,9 +7375,17 @@ class HttpCli(object):
                 for fe in dirs:
                     try:
                         hit = icur.execute(q, (vdir + fe["name"],)).fetchone()
-                        (fe["sz"], fe["tags"][".files"]) = hit
+                        if not hit and self.args.deep_dirsz:
+                            child_rp = os.path.join(abspath, fe["name"])
+                            hit = self.conn.hsrv.broker.ask(
+                                "up2k.get_volrootsize", child_rp
+                            ).get()
+                            if hit == (0, 0):
+                                hit = None
+                        if hit:
+                            (fe["sz"], fe["tags"][".files"]) = hit
                     except:
-                        pass  # 404 or mojibake
+                        pass # 404 or mojibake
 
             taglist = [k for k in lmte if k in tagset]
         else:
diff --git a/copyparty/up2k.py b/copyparty/up2k.py
index c3d7901d..d1eac162 100644
--- a/copyparty/up2k.py
+++ b/copyparty/up2k.py
@@ -528,6 +528,13 @@ class Up2k(object):
 
         return (nbytes, nfiles)
 
+    def get_volrootsize(self, realpath: str) -> tuple[int, int]:
+        cur = self.cur.get(realpath)
+        if not cur:
+            return (0, 0)
+        hit = cur.execute("select sz, nf from ds where rd='' limit 1").fetchone()
+        return hit if hit else (0, 0)
+
     def rescan(
         self, all_vols: dict[str, VFS], scan_vols: list[str], wait: bool, fscan: bool
     ) -> str: