diff --git a/src/timing.rs b/src/timing.rs
index 63ff7ca..e2d9c4e 100644
--- a/src/timing.rs
+++ b/src/timing.rs
@@ -13,10 +13,10 @@ impl Timing {
 
 impl Timing for Duration {
     fn elapsed_us(&self) -> u64 {
-        self.as_secs() as u64 * 1_000_000 + self.subsec_nanos() as u64 / 1_000
+        self.as_secs() as u64 * 1_000_000 + u64::from(self.subsec_nanos()) / 1_000
     }
     fn elapsed_ms(&self) -> u64 {
-        self.as_secs() as u64 * 1_000 + self.subsec_nanos() as u64 / 1_000_000
+        self.as_secs() as u64 * 1_000 + u64::from(self.subsec_nanos()) / 1_000_000
     }
 }