There are a bunch of apps that can do this for you, with varying degrees of automation: ShiftIt (Free/OSS): https://github.com/fikovnik/ShiftIt/tree/shiftit16

There are a bunch of apps that can do this for you, with varying degrees of automation: ShiftIt (Free/OSS): https://github.com/fikovnik/ShiftIt/tree/shiftit16 https://github.com/fikovnik/ShiftIt/tree/shiftit16 DoublePane ($3): http://5amcode.com/ http://5amcode.com/ Tyler ($10): http://blog.reflare.com/tagged/tyler http://blog.reflare.com/tagged/tyler SizeUp ($13): http://www.irradiatedsoftware.com/sizeup/ http://www.irradiatedsoftware.com/sizeup/ Divvy ($14): http://mizage.com/divvy/ http://mizage.com/divvy/ There are some old versions of ShiftIt available in the GitHub downloads, but you might want to compile a more recent version yourself. It's what I use on my 11" MacBook Air, where I mostly use the left-half, right-half, full-screen, and center-window commands. If your use case would be similar, DoublePane might be an easier choice, though it doesn't look like it does centering.