diff --git a/doc/conf.py.in b/doc/conf.py.in
index 1219c73e05d9a4047ac23d72dcc449f8581265eb..d47f5add2ef4cbaec19ec243afe2c606166be915 100644
--- a/doc/conf.py.in
+++ b/doc/conf.py.in
@@ -300,6 +300,6 @@ rst_epilog = """
 """ % project
 
 # increase default timeout (5s) for linkcheck
-linkcheck_timeout = 15.0
+linkcheck_timeout = 15
 
 #  LocalWords:  cmake