diff --git a/debian/rules b/debian/rules
index 273b989..cf1f840 100755
--- a/debian/rules
+++ b/debian/rules
@@ -15,7 +15,7 @@ LDFLAGS += -L/usr/lib/$(DEB_HOST_MULTIARCH)/nss
 
 # Deterministic "build number". Format is defined in ./buildnum.pl
 BUILD_DATE := $(shell dpkg-parsechangelog --show-field Date)
-BUILDNUM := $(shell date --date="$(BUILD_DATE)" +%Y.%j.%H%M)
+BUILDNUM := $(shell date --utc --date="$(BUILD_DATE)" +%Y.%j.%H%M)
 
 override_dh_auto_configure:
 	dh_auto_configure -- \