Windows Calculator inspired. Sharper everywhere else.

Roselt Calculator brings everyday math and advanced tools into one refined app.

Roselt Calculator is heavily inspired by Windows Calculator, then expands the formula with standard, scientific, programmer, graphing, date, history, memory, and unit conversion tools in a faster, more polished experience that runs entirely in the browser.

Open calculator See what it includes

13+: conversion categories and workflows
PWA: installable on desktop and mobile
Local: history and memory stay in your browser

Responsive layouts for phone, tablet, and desktop.

Built for quick daily math and deeper technical workflows.

Why this app

A single calculator surface for everyday math and specialized tasks.

Multiple modes, one interface

Switch between standard, scientific, programmer, graphing, date, and converter tools without leaving the same shell.

Made to feel fast

Keyboard support, persistent state, and focused layouts keep the app usable for repeat work, not just quick demos.

Install when you want

Use it in the browser first, then pin it as an installable PWA when you want a dedicated desktop or mobile experience.

Modes

Purpose-built tools behind the same familiar chrome.

The design starts with Windows Calculator familiarity, then pushes further with broader workflows, cleaner responsiveness, and a better installable web experience.

StandardCore arithmetic with history and memory support.

ScientificFunctions, constants, and advanced operations in a compact layout.

ProgrammerBitwise tools, alternate bases, and binary inspection for technical work.

GraphingPlot expressions and adjust the viewport without leaving the browser.

DateCalculate ranges and offsets for practical scheduling and planning.

ConverterConvert currency, time, area, speed, pressure, data, and more.

Install and go

Keep the web convenience. Add app-like presence.

Roselt Calculator runs entirely client side, supports installation as a progressive web app, and keeps your working state close at hand whether you open it in a tab or as a standalone window.

Desktop ready Install from Chromium-based browsers for a dedicated windowed experience.

Mobile friendly Responsive layouts adapt to touch screens without reducing the feature set.

Private by default History, memory, and preferences stay in local browser storage.

Themes and languages

Browse the live theme gallery and the full supported language list.

Roselt Calculator supports a broad set of interface languages and a growing collection of themes, including more expressive styles like Aurora, Terminal, and Unicorn. The public showcase page uses live calculator previews so you can inspect each theme before opening the app.

Browse themes & languages Open settings in the app

Live previews Every theme card is rendered from the actual calculator shell in read-only mode.

Theme-specific branding Each theme now keeps the same Roselt Calculator mark while tinting it with that theme's palette.

Full language index The public showcase lists every currently supported interface language in one place.

Ready to try it

Start with the standard calculator and explore from there.

Open the app directly, or install it later once it earns a place in your daily toolkit.

Launch Roselt Calculator Jump to graphing mode