diff --git a/debian/rules b/debian/rules
index 6f5204c..e06b214 100755
--- a/debian/rules
+++ b/debian/rules
@@ -3,7 +3,7 @@
 #export DEB_BUILD_OPTIONS=nocheck
 export PYBUILD_NAME=latexcodec
 
-DEBDATE := $(shell dpkg-parsechangelog -Sdate | date -u +%F)
+DEBDATE := $(shell dpkg-parsechangelog -Sdate | date -u -f- +%F)
 
 %:
 	dh $@ --with python2,python3,sphinxdoc --buildsystem=pybuild