diff --git a/nixos/modules/services/misc/nix-daemon.nix b/nixos/modules/services/misc/nix-daemon.nix
index 973575570612..9a8116a03e88 100644
--- a/nixos/modules/services/misc/nix-daemon.nix
+++ b/nixos/modules/services/misc/nix-daemon.nix
@@ -117,11 +117,11 @@ in
 
       buildCores = mkOption {
         type = types.int;
-        default = 1;
+        default = 0;
         example = 64;
         description = ''
           This option defines the maximum number of concurrent tasks during
-          one build. It affects, e.g., -j option for make. The default is 1.
+          one build. It affects, e.g., -j option for make.
           The special value 0 means that the builder should use all
           available CPU cores in the system. Some builds may become
           non-deterministic with this option; use with care! Packages will