An Alberta family farm that has become famous for its annual corn mazes has now grown one that's also the world's largest QR code.

The Kraay family near Lacombe say they just got a certificate from Guinness World Records for the code, which measures about 29,000 square metres.

QR codes can be scanned with a smartphone, which then directs users to a website.

The Kraay's code directs people to the website for their mazes.

To prove it works, they flew over their farm in a helicopter and held a phone out the window.

The family has grown corn mazes for the past 13 years. Visitors can pay a fee and try to find their way through the puzzles.