accounted for headers which will write a row, starting offset [numeri…

…cal offset given in the form of an int tuple only], and checked to ensure max Excel cols are also not exceeded

py-polars/polars/dataframe/frame.py

@@ -3507,9 +3507,25 @@ def write_excel(
             table_start[1] + len(df.columns) - 1,
         )
 
+        # verify that the number of rows and columns, after accounting for an offset and a header row, is within the maximum for Excel
         excel_max_valid_rows = 1048575
-        if self.height > excel_max_valid_rows:
-            msg = "Dataframe too large to be compatible with Excel. Exceeded Excel limit of 1048575 rows of data."
+        excel_max_valid_cols = 16384
+
+        initial_row_offset = 0
+        initial_col_offset = 0
+
+        # it is just a numerical offset given in the form of a tuple
+        if isinstance(position, tuple):
+            initial_row_offset, initial_col_offset = position
+
+        total_rows = self.height + initial_row_offset
+        if include_header:
+            total_rows += 1
+
+        total_cols = self.width + initial_col_offset
+
+        if total_rows > excel_max_valid_rows or total_cols > excel_max_valid_cols:
+            msg = "Dataframe too large to be compatible with Excel. Exceeded Excel limit of 1048575 rows and/or 16384 columns of data."
             raise InvalidOperationError(msg)
 
         # write table structure and formats into the target sheet