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Calc – A simple, fast command-line calculator written in Go


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A simple, fast, and intuitive command-line calculator written in Go.


Install calc as you would any other Go program:

go get


You can use calc in two ways: shell mode and command.

Shell mode

This is probably the mode you’ll want to use. It’s like the python shell or irb. The shell mode uses theterminal package provided by, which means it supports many of the shell features you know and love (like history, pasting, and the exit command).

> 1+1
> 3(5/(3-4))
> 3pi^2
> @+1
> @@@*2
> ln(-1)


You can also use calc to evaluate an expression with just a single command (i.e. without opening the shell). To do this, just use calc [expression]:

bash$ calc 1+1

Supported functions, operators, and constants

calc supports all the standard stuff, and I’m definitely adding more later (also feel free to fork and add your own!)


+, -, *, /, ^, %


sin, cos, tan, cot, sec, csc, asin, acos, atan, acot, asec, acsc, sqrt, log, lg, ln, abs


e, pi, π


Previous results can be accessed with the @ symbol. A single @ returns the result of the last computation, while multiple @ gets the nth last result, where n is the number of @s used (for example, @@ returns the second-last result, @@@@@ returns the fifth-last result).

Why not use …?

  • Google
    • Doesn’t work without an internet connection
    • Slower
    • Doesn’t show previous computations, so you end up with multiple tabs open at once.
  • Spotlight (on OS X)
    • No history
    • Switching between Spotlight and other windows isn’t too fun
  • Python/IRB
    • Requires use of a separate math module for most functions and constants
    • A little bit slower to start up
  • bc
    • Limited number of built-in functions; these have shortened (not too intuitive) names as well.

The alternatives above are all great, and have their own advantages over calc. I highly recommend looking into these if you don’t like how calc works.

More information can be found on:

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