How to calculate the watts for the right power supply?

[YouTube]

hi people im trying to build one atm, but i was wondering how do u calculate the watts for the right power supply, i have a rough idea but cant really get it right, i hear theres alot of factors such as 3, 5, and 12 watt rails that u have to account for. so ya idk lol i never liked math or numbers, if anyone can give me a hand that'd be cool

thanks

 

[John]

Post your rig specs and we'll calculate it for you. Otherwise try the eXtreme PSU calc for a rough estimate, and be sure to select the correct system type or the numbers will be way off.