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created 2006 · complexity basic · version 6.0

Here is how to define and use a calculator, using embedded Python.

These two lines go in your vimrc:

:command! -nargs=+ Calc :py print <args>
:py from math import *

Now use it inside Vim:

:Calc 2**10+5,2**16,2**128
1029 65536 340282366920938463463374607431768211456
:Calc sin(pi/2), log(10)
1.0 2.302585

You have to have Vim compiled with Python support, and have Python on your machine. Use :version to see which features are included in your Vim.

If you don't have Python support in your Vim, but do have a python command, use this instead

command! -nargs=+ Calc :!python -c "from math import *; print <args>"

You also get complex numbers and other goodies. Google for Python and math. Here is an example from complex math:

:py from cmath import *
:Calc exp(pi*1j) , " Euler famous identify e^i.pi = -1"

:Calc sum(range(1,100+1)), "Gauss' famous identity sum(1,100)"



These days, Vim Python support in Windows is usually via a dll, installed separately from Vim: :version shows +python/dyn. Go to to get the Python installer.

To check whether you have Python software that Vim can use (either statically linked or dynamically findable), do :echo has('python') — 0 (zero) means "no", anything else (normally 1) means "yes".


If your Vim (7.2 or later) is compiled with +float, you can do scientific calculations in Vim even without Python.

  • Use the numeric operators (except %) and floating point functions defined by Vim, see
  • Exponentiation is pow(base,exponent), not **
  • :echo gives you 6-digit precision by default, use printf() for user-specified precision, up to about 15 significant digits on an Intel PC (I don't know how many on a Mac PPC or an an IBM System-z).
  • If you can lay hands on (or compile) a Vim patched with Bill McCarthy's additional floating-point functions (#7 in the list), you won't need to know trigonometric formulas for "missing" functions such as tan(), asin(), atan2() etc., and you'll be able to use acos(-1) rather than 4*atan(1) for π, exp(1) rather than a literal value for e.
Tonymec 03:27, May 5, 2010 (UTC)
  • These extra floating point functions will be part of Vim 7.3. They were included in the pre-release on May 21, 2010. JamesVega 18:53, May 21, 2010 (UTC)