diff --git a/lib/ippool.c b/lib/ippool.c
index d9164a3..03323e2 100644
--- a/lib/ippool.c
+++ b/lib/ippool.c
@@ -215,7 +215,7 @@
 			flags |= IPPOOL_NONETWORK;
 		}
 
-		dynsize = (1 << (addr.len*8 - addrprefixlen)) -1;
+		dynsize = (1 << (addr.len*8 - addrprefixlen));
 		if (flags & IPPOOL_NONETWORK)	/* Exclude network address from pool */
 			dynsize--;
 		if (flags & IPPOOL_NOGATEWAY)	/* Exclude gateway address from pool */