Flutter Calculator Widget

Flutter Calculator Widget

Flutter Calculator Widget

A simple, smart and powerful Flutter calculator widget.


  • Basic arithmetic: plus, minus, multiply, divide, %, brackets.
  • Real-Time calculating.
  • Prevent to input the invalid symbol.
  • Auto-resize the formula or result font size to adapt the text box’s boundary.
  • Supports undo and redo.
  • Supports to relocate and input symbols.
  • Can be used as an embedded widget or a dialog.
  • [WIP] Supports to specify the result’s precision.
  • [WIP] Supports to copy and past the formula and the results.


Flutter Calculator Widget

Getting Started

  • Add dependency to your pubspec.yaml:
      url: git://github.com/flytreeleft/flutter_calculator.git
      # Use the developing version
      ref: master
      # or use the release version
      #ref: v0.1.0
  • Import package import 'package:flutter_calculator/flutter_calculator.dart'; and call await showCalculator(context: context); in your code:
import 'package:flutter/material.dart';

import 'package:flutter_calculator/flutter_calculator.dart';

void main() => runApp(FlutterCalculatorExample());

class FlutterCalculatorExample extends StatelessWidget {
  Widget build(BuildContext context) {
    return MaterialApp(
      // ...
      home: const HomePage(title: 'Flutter Calculator Example'),

class HomePage extends StatefulWidget {
  _HomePageState createState() => _HomePageState();

class _HomePageState extends State<HomePage> {
  final TextEditingController _textController = TextEditingController(text: '0.00');

  void dispose() {

  Widget build(BuildContext context) {
    return Scaffold(
      // ...
      body: TextField(
        showCursor: false,
        readOnly: true,
        controller: this._textController,
        onTap: () => this._showCalculatorDialog(context),

  void _showCalculatorDialog(BuildContext context) async {
    final result = await showCalculator(context: this.context) ?? 0.00;

    this._textController.value = this._textController.value.copyWith(
          text: result.toStringAsFixed(2),


Apache License 2.0



Source Code

Please Visit Flutter Calculator Widget Source Code at GitHub