What Size Pillow will fit a "Standard Size" Pillow Sham?

I just bought a King Size Mattress.. and I found this awesome king Duvet Set online that came with two Standard Size Pillow Shams. Will a normal Size Pillow fit or do I need to buy King Size pillows for the shams? The description did not give me any measurements, it just said "Standard Size". I don't know if that means Standard Pillow size or standard king pillow size to be honest. I dont want to buy two King Size pillows and not have them fit inside the shams or two standard pillows that are too small for the shams.

Take a sham with you when you buy your pillows. Then, just try them on!

Nate Berkus Patmos 600 Thread Count Duvet and Sham Set