What PSU wattage for this build?

[ClassicRyu]

Hello all. Can anyone recommend a PSU wattage for the following build? I do NOT plan to overclock.

MB: Z170 Chipset
CPU: Intel Core i5 6600K
RAM: 2 x DDR4 8GB Corsair Vengeance 2133MHz (16GB TOTAL)
GFX: 1 x Nvidia GeForce GTX 1050 Ti
HDD: 3 x Western Digital 2TB SATA 7200RPM
FANS: 3 x 120mm, 1 x 140mm
OPTICAL: 1 x DVD-RW drive, 1 x Blu Ray drive

I've used 6 PSU Calculators on the Internet, and they've given varied results that ranged from 400W - 700W.

Any help will be most appreciated, thanks in advance.

 

[ClassicRyu]

Thanks for the replies guys.

Changed my mind on the graphics card - might go for the Radeon RX 470 instead.

As for the PSU, I've set no more than £50 for it. I'm looking at the Corsair VS 550W or the Corsair CX 500W. Right now, leaning towards the VS 550. Are the Corsair VS series PSUs reliable?

Thanks in advance.