diff --git a/Makefile b/Makefile
index 94b9a3c341f..3c952faefcf 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,8 @@ BUILDTAGS ?= seccomp urfave_cli_no_docs
 BUILDTAGS += $(EXTRA_BUILDTAGS)
 
 COMMIT ?= $(shell git describe --dirty --long --always)
-VERSION ?= $(shell cat ./VERSION)
+EXTRA_VERSION :=
+VERSION := $(shell cat ./VERSION)$(EXTRA_VERSION)
 LDFLAGS_COMMON := -X main.gitCommit=$(COMMIT) -X main.version=$(VERSION)
 
 GOARCH := $(shell $(GO) env GOARCH)
diff --git a/README.md b/README.md
index 2c855e3c23e..88497c16945 100644
--- a/README.md
+++ b/README.md
@@ -86,6 +86,17 @@ sudo make install
 
 `runc` will be installed to `/usr/local/sbin/runc` on your system.
 
+#### Version string customization
+
+You can see the runc version by running `runc --version`. You can append a custom string to the
+version using the `EXTRA_VERSION` make variable when building, e.g.:
+
+```bash
+make EXTRA_VERSION="+build-1"
+```
+
+Bear in mind to include some separator for readability.
+
 #### Build Tags
 
 `runc` supports optional build tags for compiling support of various features,