diff --git a/src/uu/numfmt/src/format.rs b/src/uu/numfmt/src/format.rs
index 7c4ad723be8..0512779ca37 100644
--- a/src/uu/numfmt/src/format.rs
+++ b/src/uu/numfmt/src/format.rs
@@ -79,7 +79,7 @@ fn parse_suffix(s: &str) -> Result<(f64, Option<Suffix>)> {
         Some('E') => Some((RawSuffix::E, with_i)),
         Some('Z') => Some((RawSuffix::Z, with_i)),
         Some('Y') => Some((RawSuffix::Y, with_i)),
-        Some('0'..='9') => None,
+        Some('0'..='9') if !with_i => None,
         _ => return Err(format!("invalid suffix in input: {}", s.quote())),
     };
 
diff --git a/tests/by-util/test_numfmt.rs b/tests/by-util/test_numfmt.rs
index be46d7891aa..b11526e484f 100644
--- a/tests/by-util/test_numfmt.rs
+++ b/tests/by-util/test_numfmt.rs
@@ -208,11 +208,16 @@ fn test_should_report_invalid_empty_number_on_blank_stdin() {
 
 #[test]
 fn test_should_report_invalid_suffix_on_stdin() {
-    new_ucmd!()
-        .args(&["--from=auto"])
-        .pipe_in("1k")
-        .run()
-        .stderr_is("numfmt: invalid suffix in input: '1k'\n");
+    for c in b'a'..=b'z' {
+        new_ucmd!()
+            .args(&["--from=auto"])
+            .pipe_in(format!("1{}", c as char))
+            .run()
+            .stderr_is(format!(
+                "numfmt: invalid suffix in input: '1{}'\n",
+                c as char
+            ));
+    }
 
     // GNU numfmt reports this one as “invalid number”
     new_ucmd!()