diff --git a/src/panels/config/core/ha-config-system-navigation.ts b/src/panels/config/core/ha-config-system-navigation.ts
index 1da597e734..e895d94bb1 100644
--- a/src/panels/config/core/ha-config-system-navigation.ts
+++ b/src/panels/config/core/ha-config-system-navigation.ts
@@ -87,7 +87,9 @@ class HaConfigSystemNavigation extends LitElement {
             description = this._storageInfo
               ? this.hass.localize("ui.panel.config.storage.description", {
                   percent_used: `${Math.round(
-                    (this._storageInfo.used / this._storageInfo.total) * 100
+                    ((this._storageInfo.total - this._storageInfo.free) /
+                      this._storageInfo.total) *
+                      100
                   )}${blankBeforePercent(this.hass.locale)}%`,
                   free_space: `${this._storageInfo.free} GB`,
                 })
diff --git a/src/panels/config/storage/storage-breakdown-chart.ts b/src/panels/config/storage/storage-breakdown-chart.ts
index 703e795675..95a2ceb75b 100644
--- a/src/panels/config/storage/storage-breakdown-chart.ts
+++ b/src/panels/config/storage/storage-breakdown-chart.ts
@@ -105,9 +105,11 @@ export class StorageBreakdownChart extends LitElement {
       storageInfo: HostDisksUsage | null | undefined
     ) => {
       let totalSpaceGB = hostInfo.disk_total;
-      let usedSpaceGB = hostInfo.disk_used;
       let freeSpaceGB =
         hostInfo.disk_free || hostInfo.disk_total - hostInfo.disk_used;
+      // hostInfo.disk_used doesn't include system reserved space,
+      // so we calculate used space based on total and free space
+      let usedSpaceGB = totalSpaceGB - freeSpaceGB;
 
       if (storageInfo) {
         const totalSpace =