I second that. Great program. Not only does Qalculate! also handle binary operations and numbers of any base of your choice (including hex, octal, binary), both for output and input (even when working in another base, e.g. when the output mode is set to decimal, you can just input hexadecimal values such as 0x1AF and Qalculate! will understand)…
… but most importantly it can calculate with units and show the result converted to your liking e.g. you can write
10 Nm×2pi×20/minute to W and Qalculate will show the result as 209,4395102 W. When you get used to that, you don't want to use any calculator that doesn't have that feature any more.
Second that also as a cli `qalc`. Use it nearly every day, to convert units and quickly qalculate that would take way longer when opening a gui or pulling out my phone.
