diff --git a/Plugin/unraid/include/common.php b/Plugin/unraid/include/common.php
index aaf3fa9..f6e94f9 100644
--- a/Plugin/unraid/include/common.php
+++ b/Plugin/unraid/include/common.php
@@ -448,8 +448,11 @@ function vv_disk_entry(array $d, string $key, string $role = 'data'): ?array {
         'name'      => $name,
         'device'    => $d['device'] ?? $key,
         'role'      => $role,
-        'size_gb'   => round($size_kb / 1048576, 1),
-        'used_gb'   => round($used_kb / 1048576, 1),
+        // disks.ini is KiB. This path was arithmetically right and still disagreed with the API
+        // path by 2.4% and with Unraid's own Main page by 7.4% — it produced GiB under a "GB"
+        // name. Decimal GB, so both sources of the same disk now land on the same number.
+        'size_gb'   => round($size_kb * 1024 / 1e9, 1),
+        'used_gb'   => round($used_kb * 1024 / 1e9, 1),
         'pct'       => (!$isParity && $size_kb > 0) ? round($used_kb / $size_kb * 100, 1) : null,
         'temp'      => is_numeric($tempRaw) ? (int)$tempRaw : null,
         'transport' => $d['transport'] ?? 'ata',
@@ -785,7 +788,7 @@ function vv_remote_hosts_stats(): array {
             $availBytes = (float)($mMem['available'] ?? 0);
             $memPct = $totalBytes > 0 ? (int)round(($totalBytes - $availBytes) / $totalBytes * 100) : 0;
         }
-        $memTotalGb = isset($mMem['total']) ? _vv_api_bytes_to_gb((float)$mMem['total']) : 0;
+        $memTotalGb = isset($mMem['total']) ? _vv_api_bytes_to_gib((float)$mMem['total']) : 0;
 
         $uptimeRaw = $os['uptime'] ?? '';
         if (is_numeric($uptimeRaw)) {
diff --git a/Plugin/unraid/include/unraid_api.php b/Plugin/unraid/include/unraid_api.php
index 59f986f..58e3ee2 100644
--- a/Plugin/unraid/include/unraid_api.php
+++ b/Plugin/unraid/include/unraid_api.php
@@ -134,13 +134,26 @@ GQL;
 
 // ── Disk data helpers ─────────────────────────────────────────────────────────
 
-// API size fields (BigInt) are in bytes on this schema.
-// Heuristic: if raw > 100 billion → bytes; else → KB (covers both possible encodings).
-function _vv_api_bytes_to_gb(float $raw): float {
-    return $raw > 100_000_000_000
-        ? round($raw / (1024 ** 3), 1)
-        : round($raw / (1024 ** 2), 1);
-}
+// The API mixes three units and never says so. Measured against df and /var/local/emhttp/disks.ini
+// on 7.3.2, per field:
+//   metrics.memory.*   real bytes
+//   disk size          KiB   — 1024-byte units, the raw device
+//   disk fsSize/fsUsed kB    — 1000-byte units, the filesystem
+// disks.ini fsSize * 1024 and API fsSize * 1000 agree to the digit, which is what pins it down.
+//
+// This replaced one helper that guessed the unit from magnitude — "> 100 billion means bytes,
+// else KB". It was wrong three ways at once. Every filesystem size read 2.4% high because kB got
+// a KiB divisor; any memory total under 100 GB fell down the KB branch, so HOST2's 64 GB would
+// have reported as 65536 GB; and a disk is only ever one of these units regardless of its size,
+// so magnitude was never evidence of anything. Convert by which field it came from, not how big
+// the number is.
+function _vv_api_bytes_to_gib(float $bytes): float { return round($bytes / (1024 ** 3), 1); }
+
+// Capacity is reported the way drives are sold and the way Unraid's own Main page reports it —
+// decimal GB. A 12 TB disk reads 12000 GB here, not 10914 GiB wearing a "GB" label. Memory stays
+// binary above, because 128 GB of RAM genuinely is 125.8 GiB and every tool on the box says so.
+function _vv_api_fs_gb(float $kb): float   { return round($kb  * 1000 / 1e9, 1); }   // fsSize/fsUsed
+function _vv_api_dev_gb(float $kib): float { return round($kib * 1024 / 1e9, 1); }   // size, disks.ini
 
 // Map ArrayDiskType enum → role string used by the rest of the plugin.
 // Unraid 6.9 used CACHE; 6.10+ renamed pools to POOL. FLASH is the USB boot drive (skip).
@@ -164,19 +177,26 @@ function vv_api_disk_entry(array $d, string $role = '', int $ini_used_kb = 0): ?
         // Parity disks have no filesystem — use raw size only.
         $sizeRaw = (float)($d['size'] ?? 0);
         if ($sizeRaw <= 0) return null;
-        $sizeGb  = _vv_api_bytes_to_gb($sizeRaw);
+        $sizeGb  = _vv_api_dev_gb($sizeRaw);
         $usedGb  = 0.0;
         $pct     = null;
     } else {
-        // Data/cache disks: prefer fsSize/fsUsed; fall back to size if unmounted.
-        $sizeRaw = (float)($d['fsSize'] ?? $d['size'] ?? 0);
-        if ($sizeRaw <= 0) return null;
+        // Data/cache disks: prefer fsSize/fsUsed; fall back to size if unmounted. The fallback
+        // changes the unit as well as the source — fsSize is kB, size is KiB — so the two cannot
+        // collapse into one variable and share a conversion the way they used to.
+        $fsRaw = (float)($d['fsSize'] ?? 0);
+        if ($fsRaw > 0.0) {
+            $sizeGb = _vv_api_fs_gb($fsRaw);
+        } else {
+            $devRaw = (float)($d['size'] ?? 0);
+            if ($devRaw <= 0) return null;
+            $sizeGb = _vv_api_dev_gb($devRaw);
+        }
         $usedRaw = (float)($d['fsUsed'] ?? 0);
-        $sizeGb  = _vv_api_bytes_to_gb($sizeRaw);
         if ($usedRaw > 0.0) {
-            $usedGb = _vv_api_bytes_to_gb($usedRaw);
+            $usedGb = _vv_api_fs_gb($usedRaw);
         } elseif (!($d['isSpinning'] ?? true) && $ini_used_kb > 0) {
-            $usedGb = round($ini_used_kb / 1048576, 1);
+            $usedGb = _vv_api_dev_gb((float)$ini_used_kb);   // disks.ini is KiB, not kB
         } else {
             $usedGb = 0.0;
         }
@@ -211,8 +231,8 @@ function vv_api_node_metrics(?array $d): array {
     if (!$d) return [];
     $cpu = (int)round((float)($d['metrics']['cpu']['percentTotal'] ?? 0));
     $mem = $d['metrics']['memory'] ?? [];
-    $ramUsed = isset($mem['used'])  ? _vv_api_bytes_to_gb((float)$mem['used'])  : null;
-    $ramTot  = isset($mem['total']) ? _vv_api_bytes_to_gb((float)$mem['total']) : null;
+    $ramUsed = isset($mem['used'])  ? _vv_api_bytes_to_gib((float)$mem['used'])  : null;
+    $ramTot  = isset($mem['total']) ? _vv_api_bytes_to_gib((float)$mem['total']) : null;
 
     $disks  = $d['array']['disks']    ?? [];
     $caches = $d['array']['caches']   ?? [];
@@ -221,8 +241,8 @@ function vv_api_node_metrics(?array $d): array {
     foreach (array_merge($disks, $caches) as $dk) {
         $sz = (float)($dk['fsSize'] ?? 0);
         if ($sz <= 0) continue;
-        $totGb  += _vv_api_bytes_to_gb($sz);
-        $usedGb += _vv_api_bytes_to_gb((float)($dk['fsUsed'] ?? 0));
+        $totGb  += _vv_api_fs_gb($sz);
+        $usedGb += _vv_api_fs_gb((float)($dk['fsUsed'] ?? 0));
     }
     $temps = array_filter(
         array_merge(array_column($disks,'temp'), array_column($caches,'temp'), array_column($pars,'temp')),
@@ -264,7 +284,7 @@ function vv_local_host_stats(): array {
         $tot = (float)($mem['total'] ?? 0); $avail = (float)($mem['available'] ?? 0);
         $memPct = $tot > 0 ? (int)round(($tot - $avail) / $tot * 100) : 0;
     }
-    $memTotalGb = isset($mem['total']) ? _vv_api_bytes_to_gb((float)$mem['total']) : 0;
+    $memTotalGb = isset($mem['total']) ? _vv_api_bytes_to_gib((float)$mem['total']) : 0;
 
     $uptimeRaw = $os['uptime'] ?? '';
     if (is_numeric($uptimeRaw)) {
diff --git a/Plugin/unraid/pages/monitor.php b/Plugin/unraid/pages/monitor.php
index 871661c..50699a5 100644
--- a/Plugin/unraid/pages/monitor.php
+++ b/Plugin/unraid/pages/monitor.php
@@ -738,7 +738,9 @@ function vvTempColor(tempC, transport) {
   return tempC >= crit ? '#f44336' : tempC >= warn ? '#ff9800' : '#4caf50';
 }
 
-function vvFmt(v) { return v >= 1024 ? (v / 1024).toFixed(1) + ' TB' : v + ' GB'; }
+// Capacity only — size_gb/used_gb are decimal GB, so TB is 1000 of them. vvFmtGb below is the
+// binary one and stays binary: it formats cumulative bytes read/written, not drive capacity.
+function vvFmt(v) { return v >= 1000 ? (v / 1000).toFixed(1) + ' TB' : v + ' GB'; }
 
 function vvFmtRate(mbs) {
   if (mbs >= 1000) return (mbs / 1024).toFixed(1) + ' GB/s';