diff --git a/README.md b/README.md
index 783a190..9724efb 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,7 @@ See [`.github/workflows/ci.yml`](.github/workflows/ci.yml) for a full example.
 | `nix-build-group-id`     | The Nix build group GID                                                                                                                                                                               | integer                                    |                                           |
 | `nix-build-group-name`   | The Nix build group name                                                                                                                                                                              | string                                     |                                           |
 | `nix-build-user-base`    | The Nix build user base UID (ascending)                                                                                                                                                               | integer                                    |                                           |
+| `nix-build-user-count`   | The number of build users to create                                                                                                                                                                   | integer                                    | 32                                        |
 | `nix-build-user-prefix`  | The Nix build user prefix (user numbers will be postfixed)                                                                                                                                            | string                                     |                                           |
 | `nix-installer-branch`   | The branch of `nix-installer` to use (conflicts with the `nix-installer-tag`, `nix-installer-revision`, and `nix-installer-branch`)                                                                   | string                                     |                                           |
 | `nix-installer-pr`       | The pull request of `nix-installer` to use (conflicts with `nix-installer-tag`, `nix-installer-revision`, and `nix-installer-branch`)                                                                 | integer                                    |                                           |