diff --git a/docs/nixos_build_spec.md b/docs/nixos_build_spec.md
index 5a472e6..da7339c 100644
--- a/docs/nixos_build_spec.md
+++ b/docs/nixos_build_spec.md
@@ -2,6 +2,7 @@
 
 ## Disk / Boot (DO NOT BRICK WINDOWS)
 Target disk: /dev/nvme0n1
+- Size: 953.87 GiB (1024209543168 bytes), 2000409264 sectors
 - Model: PM951 NVMe SAMSUNG 1024GB
 - Sector size (logical/physical): 512 bytes / 512 bytes
 Install target is NVMe only. Do not select /dev/sdX devices in the installer.