Modern Calculator

A modern calculator UI backed by serious, reusable calculation engines. The project provides a browser calculator plus calculation engines for JavaScript, Python, Ruby, Java, Gradle, and .NET.

Modern Calculator is the interactive front end for a broader calculation-engine project.

Live GitHub Pages: https://tejas-mk2.github.io/Calculator/

Repository: https://github.com/TEJAS-MK2/Calculator

The calculator is designed to be useful as a browser application while the underlying engines are designed to be reusable in programs, libraries, CLIs, and other applications.

The web UI is a responsive calculator interface with the main calculator kept simple and advanced capabilities available from the sidebar.

The sidebar provides access to the engine and utility panels without overcrowding the main calculator.

The UI includes:

• Standard arithmetic calculator
• Responsive layout
• Dark/light theme support
• Calculation history
• Keyboard input
• Sidebar controls
• Scientific mode
• Statistics tools
• Matrix tools
• Exact arithmetic
• Advanced calculation-engine controls
• PWA/offline support
• Anime.js animation with a local fallback

• Addition, subtraction, multiplication, and division
• Percentages
• Decimal input
• Backspace and clear controls
• Expression preview
• Keyboard support

• Trigonometric functions
• Inverse and hyperbolic functions
• Logarithms and exponentials
• Roots and powers
• Constants and variables
• Scientific notation
• Implicit multiplication
• Statistics
• Number theory
• Combinatorics
• Numerical methods
• Calculus utilities
• Regression and interpolation
• Matrices and vectors

The JavaScript package also provides a BigInt-backed exact rational arithmetic engine for calculations that should not silently lose integer precision through JavaScript Number arithmetic.

The browser application includes a service worker and application shell caching so the calculator can continue to work offline after installation.

The repository contains six calculation-engine implementations. Each package is maintained as a reusable engine rather than simply being a copy of the browser calculator.

Registry: GitHub Packages — https://github.com/TEJAS-MK2/Calculator/packages
Source: https://github.com/TEJAS-MK2/Calculator/tree/main/packages/calculator-core

Node.js 24+.

Configure the @tejas-mk2 npm scope:

@tejas-mk2:registry=https://npm.pkg.github.com

Then install:

npm install @tejas-mk2/calculator-core

For GitHub Packages authentication, configure npm with a GitHub token that has package read access according to your GitHub Packages policy.

Run the package tests:

cd packages/calculator-core
npm test

Quick usage:

import { evaluate } from '@tejas-mk2/calculator-core';

console.log(evaluate('2 + 3 * 4'));

The package also exposes @tejas-mk2/calculator-core/advanced and @tejas-mk2/calculator-core/exact.

Package: https://pypi.org/project/pijush-calculator/
Source: https://github.com/TEJAS-MK2/Calculator/tree/main/python-package

Python 3.14+.

Install:

pip install pijush-calculator==0.6.0

Run the package tests:

cd python-package
python -m pytest

Quick usage:

from pijush_calculator import add

print(add(2, 3))

Package: https://rubygems.org/gems/pijush-calculator
Source: https://github.com/TEJAS-MK2/Calculator/tree/main/ruby-gem

Ruby 4.0+.

Install:

gem install pijush-calculator -v 0.6.0

Run the package tests:

cd ruby-gem
ruby -Ilib -Itest test/test_pijush_calculator.rb

Quick usage:

require "pijush_calculator"

puts PijushCalculator.add(2, 3)

Source: https://github.com/TEJAS-MK2/Calculator/tree/main/java-package
GitHub Packages: https://github.com/TEJAS-MK2/Calculator/packages

Java 25+ and Maven 3.9+.

Coordinates:

io.github.tejas-mk2:pijush-calculator:0.6.0

Add the GitHub Packages repository and dependency to Maven:

<repositories>
  <repository>
    <id>github</id>
    <url>https://maven.pkg.github.com/TEJAS-MK2/Calculator</url>
  </repository>
</repositories>

<dependency>
  <groupId>io.github.tejas-mk2</groupId>
  <artifactId>pijush-calculator</artifactId>
  <version>0.6.0</version>
</dependency>

Run the package tests:

cd java-package
mvn test

Source: https://github.com/TEJAS-MK2/Calculator/tree/main/gradle-package
GitHub Packages: https://github.com/TEJAS-MK2/Calculator/packages

Java 25+ and Gradle 9.6.1+.

Coordinates:

io.github.tejasmk2.gradle:pijush-calculator-gradle:0.6.0

Dependency:

dependencies {
    implementation "io.github.tejasmk2.gradle:pijush-calculator-gradle:0.6.0"
}

GitHub Packages repository:

https://maven.pkg.github.com/TEJAS-MK2/Calculator

Run the package tests:

cd gradle-package
gradle test
gradle build

Source: https://github.com/TEJAS-MK2/Calculator/tree/main/nuget-package
GitHub Packages: https://github.com/TEJAS-MK2/Calculator/packages

.NET 10+.

Configure GitHub Packages:

dotnet nuget add source https://nuget.pkg.github.com/TEJAS-MK2/index.json \
  --name github \
  --username YOUR_GITHUB_USERNAME \
  --password YOUR_GITHUB_TOKEN \
  --store-password-in-clear-text

Install:

dotnet add package Pijush.Calculator --version 0.6.0

Run the package tests:

cd nuget-package
dotnet test tests/Calculator.Tests.csproj

Quick usage:

using Pijush.Calculator;

Console.WriteLine(Calculator.Add(2m, 3m));

This calculator application is a hobbyist project. It is not intended to compete with commercial calculator products or claim to be a production scientific-computing platform.

The main goal of the project is different:

Build serious, powerful, reusable calculation engines.

The browser calculator is the practical demonstration and testing surface. The deeper objective is to develop calculation engines with strong expression parsing, numerical utilities, scientific functions, statistics, combinatorics, matrices, numerical methods, exact arithmetic, explicit error handling, and language-specific APIs.

The long-term direction is to make these engines increasingly capable, reliable, reusable, and useful to developers building their own applications.