diff --git a/inventaire.py b/inventaire.py
index bfa950e..f7a6372 100644
--- a/inventaire.py
+++ b/inventaire.py
@@ -394,6 +394,71 @@ def get_proxmox_role(dev_name):
     return None
 
 
+# -- Espace offline (partitions non montées) ----------------------------------
+
+def get_offline_space(dev, fstype):
+    """Lit l'espace d'une partition non montée selon son type de filesystem."""
+    if fstype in ("ext2", "ext3", "ext4"):
+        return _ext4_space(dev)
+    if fstype == "ntfs":
+        return _ntfs_space(dev)
+    if fstype == "btrfs":
+        return _btrfs_space(dev)
+    return None
+
+def _ext4_space(dev):
+    out = run(["tune2fs", "-l", dev])
+    if not out:
+        return None
+    vals = {}
+    for line in out.splitlines():
+        for key in ("Block count", "Free blocks", "Block size"):
+            if line.startswith(key + ":"):
+                try:
+                    vals[key] = int(line.split(":", 1)[1].strip().replace(",", ""))
+                except ValueError:
+                    pass
+    try:
+        total = vals["Block count"] * vals["Block size"]
+        free  = vals["Free blocks"] * vals["Block size"]
+        used  = total - free
+        return {"size_bytes": total, "used_bytes": used, "free_bytes": free,
+                "used_percent": int(used / total * 100) if total else 0}
+    except KeyError:
+        return None
+
+def _ntfs_space(dev):
+    # ntfsresize -i indique la taille minimale ≈ espace utilisé
+    out = run(["ntfsresize", "--info", "--force", dev])
+    if not out:
+        return None
+    total = used = None
+    for line in out.splitlines():
+        if "Current volume size:" in line:
+            m = re.search(r"(\d+)\s+bytes", line)
+            if m:
+                total = int(m.group(1))
+        if "You might resize at" in line:
+            m = re.search(r"(\d+)\s+bytes", line)
+            if m:
+                used = int(m.group(1))
+    if total and used:
+        return {"size_bytes": total, "used_bytes": used, "free_bytes": total - used,
+                "used_percent": int(used / total * 100) if total else 0}
+    return None
+
+def _btrfs_space(dev):
+    out = run(["btrfs", "filesystem", "show", dev])
+    if not out:
+        return None
+    # "Total devices 1 FS bytes used 10.00GiB"
+    m = re.search(r"FS bytes used\s+([\d.]+)(\w+)", out)
+    if m:
+        # approximation seulement, pas de total fiable sans montage
+        dprint(f"btrfs {dev} : espace utilisé approximatif")
+    return None  # trop imprecis sans montage
+
+
 # -- Construction des partitions ----------------------------------------------
 
 def build_partitions(children, df_map, lvm_map, home_done):
@@ -436,6 +501,16 @@ def build_partitions(children, df_map, lvm_map, home_done):
                    f"{part['used_human']} / {part['size_human']} ({part['used_percent']}%)")
         else:
             dprint(f"  partition {name} : fstype={fstype}, non montee")
+            if fstype in ("ext2", "ext3", "ext4", "ntfs", "btrfs"):
+                space = get_offline_space(f"/dev/{name}", fstype)
+                if space:
+                    part["used_bytes"]   = space["used_bytes"]
+                    part["used_human"]   = bytes_human(space["used_bytes"])
+                    part["free_bytes"]   = space["free_bytes"]
+                    part["free_human"]   = bytes_human(space["free_bytes"])
+                    part["used_percent"] = space["used_percent"]
+                    dprint(f"  partition {name} offline : "
+                           f"{part['used_human']} / {part['size_human']} ({part['used_percent']}%)")
 
         # /home users sur cette partition
         if mountpoint == "/home" and not home_done[0]: