How do I generate an Excel file in Dart?

Call Excel.createExcel to make a workbook, write values with updateCell or appendRow, then call save to get the .xlsx bytes.

Can I create an Excel file without Microsoft Excel?

Yes. The file is written as Office Open XML directly from Dart, so no Excel installation or external service is involved.

How to create an Excel file in Dart

Build an .xlsx workbook from nothing and write it out, with no template file and no Office install.

Install#

dart pub add excel_plus

import 'package:excel_plus/excel_plus.dart';

A minimal workbook#

final excel = Excel.createExcel();
final sheet = excel['Sheet1'];

sheet.updateCell(CellIndex.indexByString('A1'), TextCellValue('Hello, world!'));

final bytes = excel.save();

Writing each value type#

Wrap the Dart value in the matching CellValue. Storing a real date rather than a string is what lets Excel sort and filter it correctly.

sheet.updateCell(CellIndex.indexByString('A1'), TextCellValue('Name'));
sheet.updateCell(CellIndex.indexByString('B1'), IntCellValue(42));
sheet.updateCell(CellIndex.indexByString('C1'), DoubleCellValue(3.14));
sheet.updateCell(CellIndex.indexByString('D1'), BoolCellValue(true));
sheet.updateCell(CellIndex.indexByString('E1'), DateCellValue(year: 2026, month: 6, day: 9));
sheet.updateCell(CellIndex.indexByString('F1'), TimeCellValue(hour: 9, minute: 30, second: 0));
sheet.updateCell(
  CellIndex.indexByString('G1'),
  DateTimeCellValue(year: 2026, month: 6, day: 9, hour: 9, minute: 30),
);

Appending rows#

For tabular output you rarely want to compute addresses by hand. appendRow writes after the last filled row.

final sheet = excel['Sheet1'];

sheet.appendRow([TextCellValue('Product'), TextCellValue('Qty'), TextCellValue('Price')]);

for (final item in items) {
  sheet.appendRow([
    TextCellValue(item.name),
    IntCellValue(item.quantity),
    DoubleCellValue(item.price),
  ]);
}

Several sheets#

final excel = Excel.createExcel();

excel['Summary'].updateCell(CellIndex.indexByString('A1'), TextCellValue('Total'));
excel['Detail'].updateCell(CellIndex.indexByString('A1'), TextCellValue('Line items'));

excel.rename('Sheet1', 'Overview');
excel.delete('Detail');

Saving#

Pick whichever output the surrounding program needs.

// Bytes, for sending over the network or writing yourself.
final List<int>? bytes = excel.save();

// Straight to a file.
File('output.xlsx').writeAsBytesSync(excel.save()!);

// Trigger a download in the browser.
excel.save(fileName: 'report.xlsx');

// Encode off the main thread so a UI stays responsive.
final bytes = await excel.encodeAsync();

For a workbook too big to hold in memory, stream it out instead. See large files.