^ agree with above... as long as your hard drive cage is not facing side to side most Mid towers will fit the GTX... the standard ATX case has the hard drives facing front to back, so either move a drive out of the way or remove the tray altogether...
Dell 4K S2817Q / Logitech Z-680 / Func MS3 Mouse / Corsair K70
NZXT Source 530 / i7-3770K / Corsair H100 / ASRock Z77 Extreme4 / SoundBlaster Recon3d
Samsung 850 PRO 512GB SSD/Seagate 1TB/2TB/WD 2TB
4x4GB Corsair Vengeance 2133 / PNY GTX 980 ti/ Seasonic M12II 850W