diff --git a/README.md b/README.md
index e9a7e66..7790a53 100644
--- a/README.md
+++ b/README.md
@@ -106,6 +106,10 @@ namespace fs = ghc::filesystem;
 Be aware, as a header-only library, it is not hiding the fact, that it
 uses system includes, so they "pollute" your global namespace.
 
+There is a version macro `GHC_FILESYSTEM_VERSION` defined in case future changes
+might make it needed to react on the version, but I don't plan to break anything.
+It's the version as decimal number `(major * 10000 + minor * 100 + patch)`.
+
 
 ## Documentation
 
diff --git a/filesystem.h b/filesystem.h
index d4beac0..1f0d78e 100644
--- a/filesystem.h
+++ b/filesystem.h
@@ -100,6 +100,9 @@
 //#define LWG_2935_BEHAVIOUR
 #define LWG_2937_BEHAVIOUR
 
+// ghc::filesystem version in decimal (major * 10000 + minor * 100 + patch)
+#define GHC_FILESYSTEM_VERSION 10000L
+
 namespace ghc {
 namespace filesystem {