Apps similar to OpalCalc include SpeedCrunch, which is free and open source. Other options are Qalculate!, Numara Calculator, Numbat and Qaltex. Calculators like OpalCalc are a crowded field, with more than 50 alternatives for Windows, Linux, Mac, the web and Android.
RJ Calculator is a scientific calculator with most basic functions like trigonometric functions, logarithms and base conversion. Also, statistic calculations like standard deviation and regression.
Qlate is a combination of a calculator and a notepad for dynamic calculations. It's more powerful than a simple calculator and more intuitive than an Excel sheet. All that power and intelligence is wrapped behind a beautiful, clean and minimal user interface.
Brazil
A powerful, scriptable, modular calculator aimed at scientific, engineering or computing work. All features can be added, removed, and customised, and new features can be written in python.
United States
GlassCalc is a free, Windows calculator designed for quick input via keyboard. It forgoes the usual array of buttons for a single textbox where you can type an equation or mathematical expression, hit Enter, and get a result.
United States
United States
Wakari, now part of Anaconda, provides web-based Python data analysis via embedded iPython notebooks.
United States
