diff --git a/src/uu/base32/src/base_common.rs b/src/uu/base32/src/base_common.rs
index 7bd67276bf3..89e771c4796 100644
--- a/src/uu/base32/src/base_common.rs
+++ b/src/uu/base32/src/base_common.rs
@@ -28,8 +28,9 @@ pub const BASE_CMD_PARSE_ERROR: i32 = 1;
 ///
 /// This default is only used if no "-w"/"--wrap" argument is passed
 pub const WRAP_DEFAULT: usize = 76;
-// Fixed to 8 KiB (equivalent to std::io::DEFAULT_BUF_SIZE on most targets)
-pub const DEFAULT_BUFFER_SIZE: usize = 8 * 1024;
+
+// Fixed to 8 KiB (equivalent to `std::sys::io::DEFAULT_BUF_SIZE` on most targets)
+pub const DEFAULT_BUF_SIZE: usize = 8 * 1024;
 
 pub struct Config {
     pub decode: bool,
@@ -151,15 +152,12 @@ pub fn get_input(config: &Config) -> UResult<Box<dyn BufRead>> {
         Some(path_buf) => {
             let file =
                 File::open(path_buf).map_err_context(|| path_buf.maybe_quote().to_string())?;
-            Ok(Box::new(BufReader::with_capacity(
-                DEFAULT_BUFFER_SIZE,
-                file,
-            )))
+            Ok(Box::new(BufReader::with_capacity(DEFAULT_BUF_SIZE, file)))
         }
         None => {
             // Stdin is already buffered by the OS; wrap once more to reduce syscalls per read.
             Ok(Box::new(BufReader::with_capacity(
-                DEFAULT_BUFFER_SIZE,
+                DEFAULT_BUF_SIZE,
                 io::stdin(),
             )))
         }
diff --git a/src/uu/sort/benches/sort_bench.rs b/src/uu/sort/benches/sort_bench.rs
index 61e5f4564bb..08a23b65602 100644
--- a/src/uu/sort/benches/sort_bench.rs
+++ b/src/uu/sort/benches/sort_bench.rs
@@ -214,7 +214,7 @@ fn sort_unique_locale(bencher: Bencher, num_lines: usize) {
     });
 }
 
-/// Benchmark sorting with very long lines exceeding START_BUFFER_SIZE (8000 bytes)
+/// Benchmark sorting with very long lines exceeding `DEFAULT_BUF_SIZE` (8192 bytes)
 #[divan::bench(args = [10_000])]
 fn sort_long_line(bencher: Bencher, line_size: usize) {
     // Create files with very long lines to test buffer handling
diff --git a/src/uu/sort/src/ext_sort.rs b/src/uu/sort/src/ext_sort.rs
index 74a6e1fd7eb..e1cd8bf01c6 100644
--- a/src/uu/sort/src/ext_sort.rs
+++ b/src/uu/sort/src/ext_sort.rs
@@ -36,7 +36,8 @@ use crate::{
 use crate::{Line, print_sorted};
 
 // Note: update `test_sort::test_start_buffer` if this size is changed
-const START_BUFFER_SIZE: usize = 8_000;
+// Fixed to 8 KiB (equivalent to `std::sys::io::DEFAULT_BUF_SIZE` on most targets)
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
 
 /// Sort files by using auxiliary files for storing intermediate chunks (if needed), and output the result.
 pub fn ext_sort(
@@ -224,11 +225,7 @@ fn read_write_loop<I: WriteableTmpFile>(
     for _ in 0..2 {
         let should_continue = chunks::read(
             &sender,
-            RecycledChunk::new(if START_BUFFER_SIZE < buffer_size {
-                START_BUFFER_SIZE
-            } else {
-                buffer_size
-            }),
+            RecycledChunk::new(buffer_size.min(DEFAULT_BUF_SIZE)),
             Some(buffer_size),
             &mut carry_over,
             &mut file,