diff --git a/klippy/clocksync.py b/klippy/clocksync.py
index f32ed3cd..80ed9db6 100644
--- a/klippy/clocksync.py
+++ b/klippy/clocksync.py
@@ -66,10 +66,8 @@ class ClockSync:
         self.queries_pending = 0
         # Extend clock to 64bit
         last_clock = self.last_clock
-        clock = (last_clock & ~0xffffffff) | params['clock']
-        if clock < last_clock:
-            clock += 0x100000000
-        self.last_clock = clock
+        clock_delta = (params['clock'] - last_clock) & 0xffffffff
+        self.last_clock = clock = last_clock + clock_delta
         # Check if this is the best round-trip-time seen so far
         sent_time = params['#sent_time']
         if not sent_time:
@@ -138,10 +136,9 @@ class ClockSync:
     # misc commands
     def clock32_to_clock64(self, clock32):
         last_clock = self.last_clock
-        clock_diff = (last_clock - clock32) & 0xffffffff
-        if clock_diff & 0x80000000:
-            return last_clock + 0x100000000 - clock_diff
-        return last_clock - clock_diff
+        clock_diff = (clock32 - last_clock) & 0xffffffff
+        clock_diff -= (clock_diff & 0x80000000) << 1
+        return last_clock + clock_diff
     def is_active(self):
         return self.queries_pending <= 4
     def dump_debug(self):