diff --git a/tabulate/__init__.py b/tabulate/__init__.py
index 12a2950..5093f23 100644
--- a/tabulate/__init__.py
+++ b/tabulate/__init__.py
@@ -1607,7 +1607,8 @@ def _normalize_tabular_data(tabular_data, headers, showindex="default"):
     # pad with empty headers for initial columns if necessary
     headers_pad = 0
     if headers and len(rows) > 0:
-        headers_pad = max(0, len(rows[0]) - len(headers))
+        max_row_cols = max(len(r) for r in rows if not _is_separating_line(r)) if rows else 0
+        headers_pad = max(0, max_row_cols - len(headers))
         headers = [""] * headers_pad + headers
 
     return rows, headers, headers_pad
diff --git a/test/test_regression.py b/test/test_regression.py
index 9555676..94de686 100644
--- a/test/test_regression.py
+++ b/test/test_regression.py
@@ -420,6 +420,14 @@ def test_ragged_rows():
     assert_equal(expected, result)
 
 
+def test_ragged_rows_with_short_headers():
+    "Regression: headers should not drop columns from ragged rows (issue #494)"
+    table = [["a"], ["b", "KEEP"]]
+    expected = "\n".join(["    tail", "--  ------", "a", "b   KEEP"])
+    result = tabulate(table, headers=["tail"])
+    assert_equal(expected, result)
+
+
 def test_empty_pipe_table_with_columns():
     "Regression: allow empty pipe tables with columns, like empty dataframes (github issue #15)"
     table = []