The world can "run on Dunkin" with a free cup of joe on National Coffee Day.

Whether you are drawn to the corporate coffee shops or prefer to get your java from a local cafe, it’s hard to pass up free coffee—and that is exactly what Dunkin’ Donuts is offering on National Coffee Day. 

On Tuesday, September 29, Dunkin’ will offer customers a free medium hot or iced coffee (with any purchase) at participating Dunkin’ restaurants across the U.S. Dunkin’s lineup of hot and iced coffee includes its Original Blend, Dark Roast, and Dunkin’ Decaf.

If you can’t make it to a Dunkin’ on National Coffee Day, the brand is brewing up another way to give customers a taste of Dunkin’ by launching out special, limited-run Dunkin’ merchandise. This new line of apparel and accessories will have animated graphics and sayings like, “My Blood Type is Dunkin’” and “I Only Need Dunkin’ On Days Ending in Y.”

All items will be available on ShopDunkin.com beginning September 28, while supplies last.

Are you a diehard Dunkin’ fan? How will you be celebrating National Coffee Day?