diff --git a/sys/include/xtimer.h b/sys/include/xtimer.h
index b717e147fd..961b9043a3 100644
--- a/sys/include/xtimer.h
+++ b/sys/include/xtimer.h
@@ -434,7 +434,7 @@ static inline void xtimer_spin_until(uint32_t value);
 /**
  * @brief ignore some bits when comparing timer values
  *
- * (only relevant when XTIMER_MASK != 0, e.g., timers < 16bit.)
+ * (only relevant when XTIMER_MASK != 0, e.g., timers < 32bit.)
  *
  * When combining _xtimer_now() and _high_cnt, we have to get the same value in
  * order to work around a race between overflowing _xtimer_now() and OR'ing the
diff --git a/sys/xtimer/xtimer.c b/sys/xtimer/xtimer.c
index 1cb2fd25c7..a03cb55bd9 100644
--- a/sys/xtimer/xtimer.c
+++ b/sys/xtimer/xtimer.c
@@ -155,16 +155,16 @@ void xtimer_set_wakeup64(xtimer_t *timer, uint64_t offset, kernel_pid_t pid)
  * This is to avoid using long integer division functions
  * the compiler otherwise links in.
  */
-static inline uint64_t _ms_to_sec(uint64_t ms)
+static inline uint64_t _us_to_sec(uint64_t us)
 {
-    return (unsigned long long)(ms * 0x431bde83) >> (0x12 + 32);
+    return (unsigned long long)(us * 0x431bde83) >> (0x12 + 32);
 }
 
 void xtimer_now_timex(timex_t *out)
 {
     uint64_t now = xtimer_now64();
 
-    out->seconds = _ms_to_sec(now);
+    out->seconds = _us_to_sec(now);
     out->microseconds = now - (out->seconds * SEC_IN_USEC);
 }
 
diff --git a/sys/xtimer/xtimer_core.c b/sys/xtimer/xtimer_core.c
index 0b635362b8..b882dd8f74 100644
--- a/sys/xtimer/xtimer_core.c
+++ b/sys/xtimer/xtimer_core.c
@@ -120,13 +120,13 @@ void xtimer_set(xtimer_t *timer, uint32_t offset)
     }
 
     xtimer_remove(timer);
-    uint32_t target = xtimer_now() + offset;
 
     if (offset < XTIMER_BACKOFF) {
         xtimer_spin(offset);
         _shoot(timer);
     }
     else {
+        uint32_t target = xtimer_now() + offset;
         _xtimer_set_absolute(timer, target);
     }
 }