diff --git a/src/network/networkd-address.c b/src/network/networkd-address.c
index de918c3c29..d66b3a288f 100644
--- a/src/network/networkd-address.c
+++ b/src/network/networkd-address.c
@@ -1166,14 +1166,13 @@ int config_parse_prefix_lifetime(const char *unit,
                 return 0;
         }
 
-        /* a value of 0xffffffff represents infinity, 0x0 means this host is
-           not a router */
+        /* a value of 0xffffffff represents infinity */
         if (streq(lvalue, "PreferredLifetimeSec"))
                 r = sd_radv_prefix_set_preferred_lifetime(p->radv_prefix,
-                                                          (usec + USEC_PER_SEC - 1) / USEC_PER_SEC);
+                                                          DIV_ROUND_UP(usec, USEC_PER_SEC));
         else if (streq(lvalue, "ValidLifetimeSec"))
                 r = sd_radv_prefix_set_valid_lifetime(p->radv_prefix,
-                                                      (usec + USEC_PER_SEC - 1) / USEC_PER_SEC);
+                                                      DIV_ROUND_UP(usec, USEC_PER_SEC));
         if (r < 0)
                 return r;
 
diff --git a/src/network/networkd-radv.c b/src/network/networkd-radv.c
index e5be145146..af9e116936 100644
--- a/src/network/networkd-radv.c
+++ b/src/network/networkd-radv.c
@@ -55,8 +55,10 @@ int radv_configure(Link *link) {
         if (r < 0)
                 return r;
 
+        /* a value of 0xffffffff represents infinity, 0x0 means this host is
+           not a router */
         r = sd_radv_set_router_lifetime(link->radv,
-                                        link->network->router_lifetime_usec);
+                                        DIV_ROUND_UP(link->network->router_lifetime_usec, USEC_PER_SEC));
         if (r < 0)
                 return r;