diff --git a/head/sys/kern/kern_tc.c b/head/sys/kern/kern_tc.c
--- a/head/sys/kern/kern_tc.c
+++ b/head/sys/kern/kern_tc.c
@@ -2094,20 +2094,14 @@
  * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply
  * before divide conversion (to retain precision) we find that the
  * margin shrinks to 1.5 hours (one millionth of 146y).
- * With a three prong approach we never lose significant bits, no
- * matter what the cputick rate and length of timeinterval is.
  */
 
 uint64_t
 cputick2usec(uint64_t tick)
 {
-
-	if (tick > 18446744073709551LL)		/* floor(2^64 / 1000) */
-		return (tick / (cpu_tickrate() / 1000000LL));
-	else if (tick > 18446744073709LL)	/* floor(2^64 / 1000000) */
-		return ((tick * 1000LL) / (cpu_tickrate() / 1000LL));
-	else
-		return ((tick * 1000000LL) / cpu_tickrate());
+	uint64_t tr;
+	tr = cpu_tickrate();
+	return ((tick / tr) * 1000000ULL) + ((tick % tr) * 1000000ULL) / tr;
 }
 
 cpu_tick_f	*cpu_ticks = tc_cpu_ticks;
diff --git a/head/sys/kern/kern_time.c b/head/sys/kern/kern_time.c
--- a/head/sys/kern/kern_time.c
+++ b/head/sys/kern/kern_time.c
@@ -243,9 +243,10 @@
 static inline void
 cputick2timespec(uint64_t runtime, struct timespec *ats)
 {
-	runtime = cputick2usec(runtime);
-	ats->tv_sec = runtime / 1000000;
-	ats->tv_nsec = runtime % 1000000 * 1000;
+	uint64_t tr;
+	tr = cpu_tickrate();
+	ats->tv_sec = runtime / tr;
+	ats->tv_nsec = ((runtime % tr) * 1000000000ULL) / tr;
 }
 
 void
@@ -474,10 +475,7 @@
 	case CLOCK_THREAD_CPUTIME_ID:
 	case CLOCK_PROCESS_CPUTIME_ID:
 	cputime:
-		/* sync with cputick2usec */
-		ts->tv_nsec = 1000000 / cpu_tickrate();
-		if (ts->tv_nsec == 0)
-			ts->tv_nsec = 1000;
+		ts->tv_nsec = 1000000000 / cpu_tickrate() + 1;
 		break;
 	default:
 		if ((int)clock_id < 0)