How do I determine PSU wattage requirements?

[EmnicJr]

I know that there is a wattage calculator on newegg but I'd like to know how the wattage is calculated, or wether the wattage is the required or reccommended wattage for the selected components. Can anyone tell me how to calculate the wattage on my own?
this is the system:
Intel i5 Haswell 4670k (plan on overclocking)
Msi r9280x VGA
2x4GB DDR3 2133 RAM
4 120mm fans
1 120mm liquid cooling system
Ssd
Thanks

 

[Dark Lord of Tech]

A good 600w to 650w would be good for your setup.

 

[Dark Lord of Tech]

Your CPU and GPU are the main components to look at.

 

[EmnicJr]

How did you figure that out? And also, are there any brands that stand out?

 

[Dark Lord of Tech]

Seasonic , XFX = made by Seasonic , Corsair not CX Series , Antec.

Seasonic is #1