diff --git a/crates/nu-command/src/conversions/into/filesize.rs b/crates/nu-command/src/conversions/into/filesize.rs
index b3c1e65a3b9..101a9fe6f01 100644
--- a/crates/nu-command/src/conversions/into/filesize.rs
+++ b/crates/nu-command/src/conversions/into/filesize.rs
@@ -138,6 +138,7 @@ pub fn action(input: &Value, _args: &CellPathOnlyArgs, span: Span) -> Value {
         ),
     }
 }
+
 fn int_from_string(a_string: &str, span: Span) -> Result<i64, ShellError> {
     // Get the Locale so we know what the thousands separator is
     let locale = get_system_locale();
@@ -148,29 +149,35 @@ fn int_from_string(a_string: &str, span: Span) -> Result<i64, ShellError> {
     let clean_string = no_comma_string.trim();
 
     // Hadle negative file size
-    if let Some(stripped_string) = clean_string.strip_prefix('-') {
-        match stripped_string.parse::<bytesize::ByteSize>() {
+    if let Some(stripped_negative_string) = clean_string.strip_prefix('-') {
+        match stripped_negative_string.parse::<bytesize::ByteSize>() {
             Ok(n) => Ok(-(n.as_u64() as i64)),
-            Err(_) => Err(ShellError::CantConvert {
-                to_type: "int".into(),
-                from_type: "string".into(),
-                span,
-                help: None,
-            }),
+            Err(_) => Err(string_convert_error(span)),
+        }
+    } else if let Some(stripped_positive_string) = clean_string.strip_prefix('+') {
+        match stripped_positive_string.parse::<bytesize::ByteSize>() {
+            Ok(n) if stripped_positive_string.starts_with(|c: char| c.is_ascii_digit()) => {
+                Ok(n.as_u64() as i64)
+            }
+            _ => Err(string_convert_error(span)),
         }
     } else {
         match clean_string.parse::<bytesize::ByteSize>() {
-            Ok(n) => Ok(n.0 as i64),
-            Err(_) => Err(ShellError::CantConvert {
-                to_type: "int".into(),
-                from_type: "string".into(),
-                span,
-                help: None,
-            }),
+            Ok(n) => Ok(n.as_u64() as i64),
+            Err(_) => Err(string_convert_error(span)),
         }
     }
 }
 
+fn string_convert_error(span: Span) -> ShellError {
+    ShellError::CantConvert {
+        to_type: "filesize".into(),
+        from_type: "string".into(),
+        span,
+        help: None,
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
diff --git a/crates/nu-command/tests/commands/into_filesize.rs b/crates/nu-command/tests/commands/into_filesize.rs
index 2917e141dbe..d8ba88021c4 100644
--- a/crates/nu-command/tests/commands/into_filesize.rs
+++ b/crates/nu-command/tests/commands/into_filesize.rs
@@ -63,8 +63,57 @@ fn into_filesize_negative_filesize() {
 }
 
 #[test]
-fn into_negative_filesize() {
+fn into_filesize_negative_str_filesize() {
+    let actual = nu!("'-3kib' | into filesize");
+
+    assert!(actual.out.contains("-3.0 KiB"));
+}
+
+#[test]
+fn into_filesize_wrong_negative_str_filesize() {
+    let actual = nu!("'--3kib' | into filesize");
+
+    assert!(actual.err.contains("can't convert string to filesize"));
+}
+
+#[test]
+fn into_filesize_negative_str() {
     let actual = nu!("'-1' | into filesize");
 
     assert!(actual.out.contains("-1 B"));
 }
+
+#[test]
+fn into_filesize_wrong_negative_str() {
+    let actual = nu!("'--1' | into filesize");
+
+    assert!(actual.err.contains("can't convert string to filesize"));
+}
+
+#[test]
+fn into_filesize_positive_str_filesize() {
+    let actual = nu!("'+1Kib' | into filesize");
+
+    assert!(actual.out.contains("1.0 KiB"));
+}
+
+#[test]
+fn into_filesize_wrong_positive_str_filesize() {
+    let actual = nu!("'++1Kib' | into filesize");
+
+    assert!(actual.err.contains("can't convert string to filesize"));
+}
+
+#[test]
+fn into_filesize_positive_str() {
+    let actual = nu!("'+1' | into filesize");
+
+    assert!(actual.out.contains("1 B"));
+}
+
+#[test]
+fn into_filesize_wrong_positive_str() {
+    let actual = nu!("'++1' | into filesize");
+
+    assert!(actual.err.contains("can't convert string to filesize"));
+}