diff --git a/.clang-format b/.clang-format
index 16fd12253e..0b82f3c776 100644
--- a/.clang-format
+++ b/.clang-format
@@ -100,11 +100,13 @@ BreakStringLiterals: false
 # Switch statement body is always indented one level more than case labels.
 IndentCaseLabels: false
 
-# Indents directives before the hash.
+# Indents directives before the hash. Each level uses a single space for
+# indentation.
 # #if FOO
-# #  include <foo>
+# # include <foo>
 # #endif
 IndentPPDirectives: AfterHash
+PPIndentWidth: 1
 
 # Don't indent a function definition or declaration if it is wrapped after the
 # type