diff --git a/src/uu/split/src/split.rs b/src/uu/split/src/split.rs
index 86fded1d5..279e91dae 100644
--- a/src/uu/split/src/split.rs
+++ b/src/uu/split/src/split.rs
@@ -492,7 +492,7 @@ impl Settings {
                 }
                 match first.as_str() {
                     "\\0" => b'\0',
-                    s if s.as_bytes().len() == 1 => s.as_bytes()[0],
+                    s if s.len() == 1 => s.as_bytes()[0],
                     s => return Err(SettingsError::MultiCharacterSeparator(s.to_string())),
                 }
             }
diff --git a/src/uu/tac/src/tac.rs b/src/uu/tac/src/tac.rs
index 3865c61ae..d1eca4706 100644
--- a/src/uu/tac/src/tac.rs
+++ b/src/uu/tac/src/tac.rs
@@ -184,7 +184,7 @@ fn buffer_tac(data: &[u8], before: bool, separator: &str) -> std::io::Result<()>
     let mut out = BufWriter::new(out.lock());
 
     // The number of bytes in the line separator.
-    let slen = separator.as_bytes().len();
+    let slen = separator.len();
 
     // The index of the start of the next line in the `data`.
     //