diff --git a/Makefile b/Makefile
index d82bb84..cd2cc92 100644
--- a/Makefile
+++ b/Makefile
@@ -17,7 +17,10 @@ RELEASE_DIR := release
 # the binary reports dev.
 TAG         ?= $(shell git describe --tags --exact-match 2>/dev/null)
 VERSION     ?= $(patsubst v%,%,$(TAG))
-COMMIT      ?= $(shell git rev-parse HEAD 2>/dev/null)
+# -dirty when the working tree has changes, as Go itself marks vcs.modified
+# (git status --porcelain, untracked files included); empty outside git.
+DIRTY := $(shell [ -z "$$(git status --porcelain 2>/dev/null)" ] || echo -dirty)
+COMMIT      ?= $(shell git rev-parse HEAD 2>/dev/null)$(DIRTY)
 BUILD_DATE  ?= $(shell date -u +%Y-%m-%dT%H:%M:%SZ)
 LDFLAGS     := -ldflags "-s -w -X 'main.version=$(VERSION)' -X 'main.tag=$(TAG)' -X 'main.commit=$(COMMIT)' -X 'main.buildDate=$(BUILD_DATE)'"
 COVERAGE_MIN := 90