Is 500W enough for a power supply if the estimated wattage is 476w?

Apple_7

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Apr 12, 2017
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I have an intel i5-4690k and a Radeon 7970 GPU; Using PCPartpicker, my estimated wattage is 476W. I don't plan on overclocking at the moment but I do know that if I want to overclock, I'm definitely going to need a better power supply.

CPU:
Intel Core i5-4690K 3.5GHz Quad-Core Processor
CPU Cooler:
Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler
Motherboard:
ASRock H97 PRO4 ATX LGA1150 Motherboard
Memory:
G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-1600 Memory
Storage:
Seagate Barracuda 2TB 3.5" 7200RPM
Video Card:
Sapphire Radeon HD 7970 GHz Edition 3GB Video Card
Case:
Fractal Design Core 2300 ATX Mid Tower Case
Power Supply:
Corsair CX 500W 80+ Bronze Certified Semi-Modular ATX Power Supply

For future reference, what is the typical amount of wattage gap I should have between the estimated use and the capacity of the PSU?

PCPartpicker link to build:
https://pcpartpicker.com/list/FKjsgL