diff --git a/sys/netpfil/pf/pf.c b/sys/netpfil/pf/pf.c
index 4c8afca756e9..9fa2c06f4528 100644
--- a/sys/netpfil/pf/pf.c
+++ b/sys/netpfil/pf/pf.c
@@ -1567,9 +1567,11 @@ pf_state_expires(const struct pf_state *state)
 		states = V_pf_status.states;
 	}
 	if (end && states > start && start < end) {
-		if (states < end)
-			return (state->expire + timeout * (end - states) /
-			    (end - start));
+		if (states < end) {
+			timeout = (u_int64_t)timeout * (end - states) /
+			    (end - start);
+			return (state->expire + timeout);
+		}
 		else
 			return (time_uptime);
 	}