diff --git a/include/nuttx/clock.h b/include/nuttx/clock.h
index ab6f55b557e..b11b1cfc693 100644
--- a/include/nuttx/clock.h
+++ b/include/nuttx/clock.h
@@ -124,7 +124,7 @@
  * the system timer is given by USEC_PER_TICK.  This is the expected number
  * of microseconds between calls from the processor-specific logic to
  * nxsched_process_timer().  The default value of USEC_PER_TICK is 10000
- * microseconds (100KHz).  However, this default setting can be overridden
+ * microseconds (100 Hz).  However, this default setting can be overridden
  * by defining the interval in microseconds as CONFIG_USEC_PER_TICK in the
  * NuttX configuration file.
  *