diff --git a/vm/src/anystr.rs b/vm/src/anystr.rs
index ba7cd17d2..d7ad454f8 100644
--- a/vm/src/anystr.rs
+++ b/vm/src/anystr.rs
@@ -65,6 +65,10 @@ impl StartsEndsWithArgs {
         let range = adjust_indices(self.start, self.end, len);
         (self.affix, range)
     }
+
+    pub fn has_subrange(&self) -> bool {
+        self.start.is_none() && self.end.is_none()
+    }
 }
 
 fn saturate_to_isize(py_int: PyIntRef) -> isize {
@@ -194,6 +198,7 @@ pub trait AnyStr<'s>: 's {
     fn py_startsendswith<T, F>(
         &self,
         args: StartsEndsWithArgs,
+        len: usize,
         func_name: &str,
         py_type_name: &str,
         func: F,
@@ -203,11 +208,11 @@ pub trait AnyStr<'s>: 's {
         T: TryFromObject,
         F: Fn(&Self, &T) -> bool,
     {
-        let (affix, value) = if args.start.is_none() && args.end.is_none() {
+        let (affix, value) = if args.has_subrange() {
             // If it doesn't have subrange, it uses bytes operation.
-            (args.affix, self.get_bytes(0..self.bytes_len()))
+            (args.affix, self.get_bytes(0..len))
         } else {
-            let (affix, range) = args.get_value(self.chars_len());
+            let (affix, range) = args.get_value(len);
             if !range.is_normal() {
                 return Ok(false);
             }
diff --git a/vm/src/builtins/bytearray.rs b/vm/src/builtins/bytearray.rs
index 4b0fa0054..2ac4c9fd7 100644
--- a/vm/src/builtins/bytearray.rs
+++ b/vm/src/builtins/bytearray.rs
@@ -432,6 +432,7 @@ impl PyByteArray {
     fn endswith(&self, options: anystr::StartsEndsWithArgs, vm: &VirtualMachine) -> PyResult<bool> {
         self.borrow_buf().py_startsendswith(
             options,
+            self.len(),
             "endswith",
             "bytes",
             |s, x: &PyBytesInner| s.ends_with(&x.elements[..]),
@@ -447,6 +448,7 @@ impl PyByteArray {
     ) -> PyResult<bool> {
         self.borrow_buf().py_startsendswith(
             options,
+            self.len(),
             "startswith",
             "bytes",
             |s, x: &PyBytesInner| s.starts_with(&x.elements[..]),
diff --git a/vm/src/builtins/bytes.rs b/vm/src/builtins/bytes.rs
index 8e6a090e0..4209b2a5a 100644
--- a/vm/src/builtins/bytes.rs
+++ b/vm/src/builtins/bytes.rs
@@ -277,6 +277,7 @@ impl PyBytes {
     fn endswith(&self, options: anystr::StartsEndsWithArgs, vm: &VirtualMachine) -> PyResult<bool> {
         self.inner.elements[..].py_startsendswith(
             options,
+            self.len(),
             "endswith",
             "bytes",
             |s, x: &PyBytesInner| s.ends_with(&x.elements[..]),
@@ -292,6 +293,7 @@ impl PyBytes {
     ) -> PyResult<bool> {
         self.inner.elements[..].py_startsendswith(
             options,
+            self.len(),
             "startswith",
             "bytes",
             |s, x: &PyBytesInner| s.starts_with(&x.elements[..]),
diff --git a/vm/src/builtins/pystr.rs b/vm/src/builtins/pystr.rs
index ec3ea2ae7..fd3f45ce7 100644
--- a/vm/src/builtins/pystr.rs
+++ b/vm/src/builtins/pystr.rs
@@ -688,8 +688,15 @@ impl PyStr {
 
     #[pymethod]
     fn endswith(&self, args: anystr::StartsEndsWithArgs, vm: &VirtualMachine) -> PyResult<bool> {
+        let len = if args.has_subrange() {
+            self.byte_len()
+        } else {
+            self.char_len()
+        };
+
         self.as_str().py_startsendswith(
             args,
+            len,
             "endswith",
             "str",
             |s, x: &PyStrRef| s.ends_with(x.as_str()),
@@ -699,8 +706,15 @@ impl PyStr {
 
     #[pymethod]
     fn startswith(&self, args: anystr::StartsEndsWithArgs, vm: &VirtualMachine) -> PyResult<bool> {
+        let len = if args.has_subrange() {
+            self.byte_len()
+        } else {
+            self.char_len()
+        };
+
         self.as_str().py_startsendswith(
             args,
+            len,
             "startswith",
             "str",
             |s, x: &PyStrRef| s.starts_with(x.as_str()),