NumPad is described as 'Fast, lightweight web app with support for units, dates and more. It lets you keep notes and calculations in one document, gives you answers as you type, and it understands calculations like "£200 + 20%" or "2500kcal / 1 day in watts"' and is a Calculator in the education & reference category. There are more than 10 alternatives to NumPad, not only websites but also apps for a variety of platforms, including Mac, Windows, Linux and iPad apps. The best NumPad alternative is SpeedCrunch, which is both free and Open Source. Other great sites and apps similar to NumPad are Qalculate!, Hurmet, Numbat and Numi.
SpeedCrunch is a free, fast, high precision open source algebraic calculator with an intuitive interface and many features, such as variables, syntax highlighting, functions, persistent input history & more.
Germany
EU
Qalculate! is a multi-purpose cross-platform desktop calculator. It is simple to use but provides power and versatility normally reserved for complicated math packages, as well as useful tools for everyday needs (such as currency conversion and percent calculation).
SwedenEU
Hurmet is a web-based rich text editor endowed with live calculations. With it, you can create documents that do calculations and preserve an easy-to-read record of your work.
High precision scientific calculator with full support for physical units (web and terminal versions).
GermanyEU
Numi is a handy calculator app for macOS. It allows to describe tasks the natural way and instantly get an accurate answer. For example, $20 in euro - 5% discount or today + 2 weeks. Numi is not limited to simple calculations, it can solve expressions of any complexity, with...
Russia
Do you ever grab a calculator & the back of an envelope to work through an idea or problem that involves some math?
Australia
Calca is a powerful symbolic calculator that updates as you type giving you instant answers. It solves equations and simplifies complex expressions. It's also a rich Markdown text editor so that you can explain your ideas alongside your calculations.
United States
Calcbot is a simple and beautifully designed calculator for your iPhone, iPod touch and iPad. You’ll never open the built-in Calculator app again.
United States
OpalCalc is a brand new type of calculator for the PC. As easy to use as Notepad or a word processor, OpalCalc allows natural language in the sum and multi-line support so you can go back and adjust your previous calculations on the fly.
NumWorks designed an intuitive and evolutive graphing calculator to make learning maths easier.
FranceEU
Numbr is a currency calculator, a notepad that understands your calculation. You can use notes with numbers alongside each other. And all your numbers are instantly calculated as you type.
