diff --git a/libc/src/time/asctime.h b/libc/src/time/asctime.h
--- a/libc/src/time/asctime.h
+++ b/libc/src/time/asctime.h
@@ -18,5 +18,3 @@
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_TIME_ASCTIME_H
-
-#include "include/time.h"
diff --git a/libc/src/time/asctime_r.h b/libc/src/time/asctime_r.h
--- a/libc/src/time/asctime_r.h
+++ b/libc/src/time/asctime_r.h
@@ -18,5 +18,3 @@
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_TIME_ASCTIME_R_H
-
-#include "include/time.h"
diff --git a/libc/src/time/clock_gettime.cpp b/libc/src/time/clock_gettime.cpp
--- a/libc/src/time/clock_gettime.cpp
+++ b/libc/src/time/clock_gettime.cpp
@@ -17,6 +17,7 @@
 
 namespace __llvm_libc {
 
+// TODO(michaelrj): Move this into time/linux with the other syscalls.
 LLVM_LIBC_FUNCTION(int, clock_gettime,
                    (clockid_t clockid, struct timespec *tp)) {
   long ret_val =
diff --git a/libc/src/time/difftime.h b/libc/src/time/difftime.h
--- a/libc/src/time/difftime.h
+++ b/libc/src/time/difftime.h
@@ -18,5 +18,3 @@
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_TIME_DIFFTIME_H
-
-#include "include/time.h"
diff --git a/libc/src/time/gettimeofday.h b/libc/src/time/gettimeofday.h
--- a/libc/src/time/gettimeofday.h
+++ b/libc/src/time/gettimeofday.h
@@ -18,5 +18,3 @@
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_TIME_GETTIMEOFDAY_H
-
-#include "include/time.h"
diff --git a/libc/src/time/gettimeofday.cpp b/libc/src/time/gettimeofday.cpp
--- a/libc/src/time/gettimeofday.cpp
+++ b/libc/src/time/gettimeofday.cpp
@@ -16,6 +16,7 @@
 
 namespace __llvm_libc {
 
+// TODO(michaelrj): Move this into time/linux with the other syscalls.
 LLVM_LIBC_FUNCTION(int, gettimeofday,
                    (struct timeval * tv, [[maybe_unused]] void *unused)) {
   if (tv == nullptr)
diff --git a/libc/src/time/gmtime.h b/libc/src/time/gmtime.h
--- a/libc/src/time/gmtime.h
+++ b/libc/src/time/gmtime.h
@@ -18,5 +18,3 @@
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_TIME_GMTIME_H
-
-#include "include/time.h"
diff --git a/libc/src/time/gmtime_r.h b/libc/src/time/gmtime_r.h
--- a/libc/src/time/gmtime_r.h
+++ b/libc/src/time/gmtime_r.h
@@ -18,5 +18,3 @@
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_TIME_GMTIME_R_H
-
-#include "include/time.h"
diff --git a/libc/src/time/linux/clock.cpp b/libc/src/time/linux/clock.cpp
--- a/libc/src/time/linux/clock.cpp
+++ b/libc/src/time/linux/clock.cpp
@@ -27,8 +27,7 @@
     return clock_t(-1);
   }
 
-  // The above syscall gets the CPU time in seconds plus nanoseconds. We should
-  // make sure that corresponding clocks can actually be represented by clock-t.
+  // The above syscall gets the CPU time in seconds plus nanoseconds.
   // The standard requires that we return clock_t(-1) if we cannot represent
   // clocks as a clock_t value.
   constexpr clock_t CLOCK_SECS_MAX =
diff --git a/libc/src/time/mktime.h b/libc/src/time/mktime.h
--- a/libc/src/time/mktime.h
+++ b/libc/src/time/mktime.h
@@ -18,5 +18,3 @@
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_TIME_MKTIME_H
-
-#include "include/time.h"
diff --git a/libc/src/time/nanosleep.h b/libc/src/time/nanosleep.h
--- a/libc/src/time/nanosleep.h
+++ b/libc/src/time/nanosleep.h
@@ -18,5 +18,3 @@
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_TIME_NANOSLEEP_H
-
-#include "include/time.h"
diff --git a/libc/src/time/nanosleep.cpp b/libc/src/time/nanosleep.cpp
--- a/libc/src/time/nanosleep.cpp
+++ b/libc/src/time/nanosleep.cpp
@@ -15,6 +15,7 @@
 
 namespace __llvm_libc {
 
+// TODO(michaelrj): Move this into time/linux with the other syscalls.
 LLVM_LIBC_FUNCTION(int, nanosleep,
                    (const struct timespec *req, struct timespec *rem)) {
   int ret = __llvm_libc::syscall_impl(SYS_nanosleep, req, rem);
diff --git a/libc/src/time/time_utils.h b/libc/src/time/time_utils.h
--- a/libc/src/time/time_utils.h
+++ b/libc/src/time/time_utils.h
@@ -37,18 +37,21 @@
 
 struct TimeConstants {
   static constexpr int SECONDS_PER_MIN = 60;
-  static constexpr int SECONDS_PER_HOUR = 3600;
-  static constexpr int SECONDS_PER_DAY = 86400;
   static constexpr int MINUTES_PER_HOUR = 60;
+  static constexpr int HOURS_PER_DAY = 24;
   static constexpr int DAYS_PER_WEEK = 7;
   static constexpr int MONTHS_PER_YEAR = 12;
   static constexpr int DAYS_PER_NON_LEAP_YEAR = 365;
   static constexpr int DAYS_PER_LEAP_YEAR = 366;
+
+  static constexpr int SECONDS_PER_HOUR = SECONDS_PER_MIN * MINUTES_PER_HOUR;
+  static constexpr int SECONDS_PER_DAY = SECONDS_PER_HOUR * HOURS_PER_DAY;
+  static constexpr int NUMBER_OF_SECONDS_IN_LEAP_YEAR =
+      DAYS_PER_LEAP_YEAR * SECONDS_PER_DAY;
+
   static constexpr int TIME_YEAR_BASE = 1900;
   static constexpr int EPOCH_YEAR = 1970;
   static constexpr int EPOCH_WEEK_DAY = 4;
-  static constexpr int NUMBER_OF_SECONDS_IN_LEAP_YEAR =
-      (DAYS_PER_NON_LEAP_YEAR + 1) * SECONDS_PER_DAY;
 
   // For asctime the behavior is undefined if struct tm's tm_wday or tm_mon are
   // not within the normal ranges as defined in <time.h>, or if struct tm's
@@ -64,10 +67,10 @@
   static constexpr int WEEK_DAY_OF2000_MARCH_FIRST = 3;
 
   static constexpr int DAYS_PER400_YEARS =
-      (DAYS_PER_NON_LEAP_YEAR * 400 + (400 / 4) - 3);
+      (DAYS_PER_NON_LEAP_YEAR * 400) + (400 / 4) - 3;
   static constexpr int DAYS_PER100_YEARS =
-      (DAYS_PER_NON_LEAP_YEAR * 100 + (100 / 4) - 1);
-  static constexpr int DAYS_PER4_YEARS = (DAYS_PER_NON_LEAP_YEAR * 4 + 1);
+      (DAYS_PER_NON_LEAP_YEAR * 100) + (100 / 4) - 1;
+  static constexpr int DAYS_PER4_YEARS = (DAYS_PER_NON_LEAP_YEAR * 4) + 1;
 
   // The latest time that can be represented in this form is 03:14:07 UTC on
   // Tuesday, 19 January 2038 (corresponding to 2,147,483,647 seconds since the
@@ -82,6 +85,10 @@
 // "total_seconds" is the number of seconds since January 1st, 1970.
 extern int64_t update_from_seconds(int64_t total_seconds, struct tm *tm);
 
+// TODO(michaelrj): move these functions to use ErrorOr instead of setting
+// errno. They always accompany a specific return value so we only need the one
+// variable.
+
 // POSIX.1-2017 requires this.
 LIBC_INLINE time_t out_of_range() {
   libc_errno = EOVERFLOW;
@@ -114,6 +121,10 @@
   static const char *months_name[TimeConstants::MONTHS_PER_YEAR] = {
       "Jan", "Feb", "Mar", "Apr", "May", "Jun",
       "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
+
+  // TODO(michaelr): look into removing this call to __builtin_snprintf that may
+  // be emitted as a call to snprintf. Alternatively, look into using our
+  // internal printf machinery.
   int written_size = __builtin_snprintf(
       buffer, bufferLength, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
       week_days_name[timeptr->tm_wday], months_name[timeptr->tm_mon],
diff --git a/libc/src/time/time_utils.cpp b/libc/src/time/time_utils.cpp
--- a/libc/src/time/time_utils.cpp
+++ b/libc/src/time/time_utils.cpp
@@ -85,19 +85,19 @@
     numOfFourHundredYearCycles--;
   }
 
-  // The reminder number of years after computing number of
+  // The remaining number of years after computing the number of
   // "four hundred year cycles" will be 4 hundred year cycles or less in 400
   // years.
   int64_t numOfHundredYearCycles = computeRemainingYears(
       TimeConstants::DAYS_PER100_YEARS, 4, &remainingDays);
 
-  // The reminder number of years after computing number of
+  // The remaining number of years after computing the number of
   // "hundred year cycles" will be 25 four year cycles or less in 100 years.
   int64_t numOfFourYearCycles =
       computeRemainingYears(TimeConstants::DAYS_PER4_YEARS, 25, &remainingDays);
 
-  // The reminder number of years after computing number of "four year cycles"
-  // will be 4 one year cycles or less in 4 years.
+  // The remaining number of years after computing the number of
+  // "four year cycles" will be 4 one year cycles or less in 4 years.
   int64_t remainingYears = computeRemainingYears(
       TimeConstants::DAYS_PER_NON_LEAP_YEAR, 4, &remainingDays);
 
@@ -109,6 +109,8 @@
   int leapDay =
       !remainingYears && (numOfFourYearCycles || !numOfHundredYearCycles);
 
+  // We add 31 and 28 for the number of days in January and February, since our
+  // starting point was March 1st.
   int64_t yday = remainingDays + 31 + 28 + leapDay;
   if (yday >= TimeConstants::DAYS_PER_NON_LEAP_YEAR + leapDay)
     yday -= TimeConstants::DAYS_PER_NON_LEAP_YEAR + leapDay;
diff --git a/libc/test/src/time/CMakeLists.txt b/libc/test/src/time/CMakeLists.txt
--- a/libc/test/src/time/CMakeLists.txt
+++ b/libc/test/src/time/CMakeLists.txt
@@ -1,7 +1,7 @@
 add_custom_target(libc_time_unittests)
 
 add_libc_unittest(
-  asctime
+  asctime_test
   SUITE
     libc_time_unittests
   SRCS
@@ -16,7 +16,7 @@
 )
 
 add_libc_unittest(
-  asctime_r
+  asctime_r_test
   SUITE
     libc_time_unittests
   SRCS
@@ -31,7 +31,7 @@
 )
 
 add_libc_unittest(
-  clock_gettime
+  clock_gettime_test
   SUITE
     libc_time_unittests
   SRCS
@@ -41,7 +41,7 @@
 )
 
 add_libc_unittest(
-  difftime
+  difftime_test
   SUITE
     libc_time_unittests
   SRCS
@@ -51,7 +51,7 @@
 )
 
 add_libc_unittest(
-  gettimeofday
+  gettimeofday_test
   SUITE
     libc_time_unittests
   SRCS
@@ -69,7 +69,7 @@
 )
 
 add_libc_unittest(
-  gmtime
+  gmtime_test
   SUITE
     libc_time_unittests
   SRCS
@@ -81,7 +81,7 @@
 )
 
 add_libc_unittest(
-  gmtime_r
+  gmtime_r_test
   SUITE
     libc_time_unittests
   SRCS
@@ -93,7 +93,7 @@
 )
 
 add_libc_unittest(
-  mktime
+  mktime_test
   SUITE
     libc_time_unittests
   SRCS
@@ -108,7 +108,7 @@
 )
 
 add_libc_unittest(
-  nanosleep
+  nanosleep_test
   SUITE
     libc_time_unittests
   SRCS