Power consumption calculators such as the one linked are inaccurate, and often over estimate. They do this due to worst case scenarios and another theory is because they receive a larger profit from a power supply sale of higher wattage. Always best to go by professional power consumption tests using similar hardware.
That power supply tier list is outdated and contains many flaws (as with nearly all PSU tier lists). It is more misleading than helpful. It is best to go straight by professional reviews, or if you aren't sure how to analyse them, you could ask the community.
Your system will likely need under 200w while under a gaming load. A 350w, quality power supply would be more than capable, however there aren't many 350w quality PSUs on the market.
I suggest the Corsair CX450M, which is normally a cheap power supply offering good electrical performance and quality.
What exactly is your budget and where are you located?