diff --git a/PCbuild/readme.txt b/PCbuild/readme.txt
index 7c5eab2eb75a1de..72fbbba4c100e2d 100644
--- a/PCbuild/readme.txt
+++ b/PCbuild/readme.txt
@@ -105,6 +105,26 @@ the 32-bit Win32 platform.  It accepts several arguments to change
 this behavior, try `build.bat -h` to learn more.
 
 
+Custom Output Directory
+-----------------------
+
+If you want to move the build outputs to a different directory, do not use the
+standard MSBuild `/p:OutDir=` property, as CPython has many assumptions about
+where the source repository is relative to the built files. Instead, you can
+override the output directory by setting `Py_OutDir` as an environment
+variable or by passing it to build.bat (for example,
+`build.bat "/p:Py_OutDir=C:\MyOutput"`).
+
+However, be aware that the compiled binaries probably won't run directly from
+that location. If you want to make an install-shaped layout without creating the
+installer, build CPython normally first, and then use the `PC/layout` script
+with the runtime you just built, or using the `--build` and `--source` options
+to specify the directories:
+    python.bat PC/layout --<options>
+Use `-h` with that command to see all available options for customizing the
+layout.
+
+
 C Runtime
 ---------