diff --git a/src/linux/hardware.zig b/src/linux/hardware.zig
index 546f489..ce6f689 100644
--- a/src/linux/hardware.zig
+++ b/src/linux/hardware.zig
@@ -320,7 +320,7 @@ pub fn getDiskSize(disk_path: []const u8) !DiskInfo {
     }
 
     const total_size = stat.f_blocks * stat.f_frsize;
-    const free_size = stat.f_bavail * stat.f_frsize;
+    const free_size = stat.f_bfree * stat.f_frsize;
     const used_size = total_size - free_size;
 
     const used_size_percentage = (used_size * 100) / total_size;
diff --git a/src/macos/hardware.zig b/src/macos/hardware.zig
index 6b33789..2d0fd82 100644
--- a/src/macos/hardware.zig
+++ b/src/macos/hardware.zig
@@ -418,7 +418,7 @@ pub fn getDiskSize(disk_path: []const u8) !DiskInfo {
     }
 
     const total_size = stat.f_blocks * stat.f_frsize;
-    const free_size = stat.f_bavail * stat.f_frsize;
+    const free_size = stat.f_bfree * stat.f_frsize;
     const used_size = total_size - free_size;
 
     const used_size_percentage = (used_size * 100) / total_size;