Calculators

Add Hours and Minutes is a free and open source, simple calculator for adding and subtracting the time specified in hours and minutes

SpeedCrunch is a free and open source, multi-platform fast and high-precision scientific calculator controlled from the keyboard

Qalculate! – free and open source, cross-platform, simple yet powerful and versatile calculator

Elcalc is a free and open source, cross-platform simple calculator on Electron

GNOME Calculator is a free and open source, simple yet powerful calculator with advanced, financial, and programming modes