diff --git a/crates/nu-command/tests/commands/reject.rs b/crates/nu-command/tests/commands/reject.rs
index 15a0cba8a5..a2c052b3e1 100644
--- a/crates/nu-command/tests/commands/reject.rs
+++ b/crates/nu-command/tests/commands/reject.rs
@@ -141,7 +141,7 @@ fn reject_rows_with_list_spread() {
     let actual = nu!("let arg = [2 0]; [[name type size];[Cargo.toml file 10mb] [Cargo.lock file 10mb] [src dir 100mb]] | reject ...$arg | to nuon");
     assert_eq!(
         actual.out,
-        r#"[[name, type, size]; ["Cargo.lock", file, 10000000B]]"#
+        r#"[[name, type, size]; ["Cargo.lock", file, 10000000b]]"#
     );
 }
 
@@ -150,7 +150,7 @@ fn reject_mixed_with_list_spread() {
     let actual = nu!("let arg = [type 2]; [[name type size];[Cargp.toml file 10mb] [ Cargo.lock file 10mb] [src dir 100mb]] | reject ...$arg | to nuon");
     assert_eq!(
         actual.out,
-        r#"[[name, size]; ["Cargp.toml", 10000000B], ["Cargo.lock", 10000000B]]"#
+        r#"[[name, size]; ["Cargp.toml", 10000000b], ["Cargo.lock", 10000000b]]"#
     );
 }
 
diff --git a/crates/nu-command/tests/format_conversions/nuon.rs b/crates/nu-command/tests/format_conversions/nuon.rs
index 6d96566521..e4f6281c01 100644
--- a/crates/nu-command/tests/format_conversions/nuon.rs
+++ b/crates/nu-command/tests/format_conversions/nuon.rs
@@ -211,7 +211,7 @@ fn to_nuon_filesize() {
         "#
     ));
 
-    assert_eq!(actual.out, "1024B");
+    assert_eq!(actual.out, "1024b");
 }
 
 #[test]
diff --git a/crates/nuon/src/lib.rs b/crates/nuon/src/lib.rs
index 135788d69c..24a84dfd5f 100644
--- a/crates/nuon/src/lib.rs
+++ b/crates/nuon/src/lib.rs
@@ -154,7 +154,7 @@ mod tests {
 
     #[test]
     fn filesize() {
-        nuon_end_to_end("1024B", Some(Value::test_filesize(1024)));
+        nuon_end_to_end("1024b", Some(Value::test_filesize(1024)));
         assert_eq!(from_nuon("1kib", None).unwrap(), Value::test_filesize(1024));
     }
 
diff --git a/crates/nuon/src/to.rs b/crates/nuon/src/to.rs
index 10850f4313..b8281e8ffe 100644
--- a/crates/nuon/src/to.rs
+++ b/crates/nuon/src/to.rs
@@ -110,7 +110,7 @@ fn value_to_string(
         // Propagate existing errors
         Value::Error { error, .. } => Err(*error.clone()),
         // FIXME: make filesizes use the shortest lossless representation.
-        Value::Filesize { val, .. } => Ok(format!("{}B", val.get())),
+        Value::Filesize { val, .. } => Ok(format!("{}b", val.get())),
         Value::Float { val, .. } => {
             // This serialises these as 'nan', 'inf' and '-inf', respectively.
             if &val.round() == val && val.is_finite() {