How do I convert a CSV file to Excel in Dart?

Pass the CSV text to Excel.fromCsv to build a workbook, then save it as .xlsx. Use importCsv to add a CSV sheet to an existing workbook.

How do I export a spreadsheet to CSV in Dart?

Call toCsv on the sheet. Pass a CsvConfig to change the delimiter, for example to produce tab separated output.

CSV import and export

Move between .xlsx and CSV or TSV in either direction.

Install#

dart pub add excel_plus

import 'package:excel_plus/excel_plus.dart';

CSV to a workbook#

final excel = Excel.fromCsv('name,age\nAlice,30\nBob,25', sheetName: 'People');

File('people.xlsx').writeAsBytesSync(excel.save()!);

Adding a CSV sheet to a workbook you already have#

excel.importCsv('a\tb\n1\t2', sheetName: 'Tabbed', config: const CsvConfig.tsv());

A sheet back to CSV#

final csv = excel['People'].toCsv();

Type inference will not damage your data#

Values that look numeric but are not, such as a zero padded id, stay text. 007 does not become 7. Pass inferTypes: false to keep every field as text.

Messy exports#

Real CSV files often carry a comment preamble or junk rows before the header.

excel.importCsv(
  '# Sales report 2026\nname,total\nAlice,95\nBob,88',
  sheetName: 'Sales',
  config: const CsvConfig(comment: '#'),
);

CsvConfig also takes skipRows to drop leading rows and maxRows to read only a slice, plus delimiter, quoting and line ending settings.

Forcing column types#

When guessing is not good enough, declare the columns. The first row is the header, each named column is coerced to its declared type, and a value that cannot convert throws CsvParseException.

excel.importCsv('id,score\n001,9\n002,8', sheetName: 'Scores', schema: const CsvSchema(
  columns: [
    CsvColumnDef(name: 'id', type: String),
    CsvColumnDef(name: 'score', type: double),
  ],
));