The first round is on the haus.

April 7 marks National Beer Day, and German beer garden Bierhaus NYC is celebrating with a traditional keg tapping at 7 p.m., offering all patrons who attend a complimentary round of beer.

Biehaus serves up brews by Munich's Hofbräu, from seasonal taps to the classic varieties, including lagers, Hefe Weizen and more. Head there early to enjoy beer by the half liter ($8), liter ($16) and 2-liter boot ($32). Or, sample a variety of brews with a five-beer flight for $11.

In addition to traditional German fare, like pretzels and bratwurst, Bierhaus is serving up an all-day holiday special of half-off beer cheese dip and chips with the purchase of a liter.

Bierhaus NYC is at 712 Third Ave., near East 45th Street, and is open from 11:30 a.m. to 2 a.m. on Fridays. For more information, visit bierhausnyc.com.

Other deal to catch Friday include:

Jackson Heights restaurant El Maguey is serving up National Beer Day deals all night, featuring $4 Mexican brews like Corona, Pacifico, XX and Modelo Especial. (83-28 Northern Blvd., Queens, noon to 4 a.m.)

Eateries at Grand Central Terminal are offering a variety of beer discounts to celebrate the holiday. Beer Table’s takeaway draught beer — offered in 64 oz. growlers and capped mason jars — will be 20 percent off. La Chula NYC is serving up $3 Modelo beers. (89 E. 42nd St., Manhattan)

Go all-out with a Coney Island Brewing Co. sponsored pub crawl, starting at midtown's House of Brews. Expect drink specials and giveaways. The pub crawl is free to attend, but purchase a ticket online in advance to enjoy your first brew on the house. (302 W. 51st St., Manhattan, 5 to 10 p.m., $3)

Taste a variety of German brews at Staten Island’s Nurnberger Bierhaus. Sample 21 different types of beers and take home a complimentary mug. (817 Castletown Ave., Staten Island, 7 p.m., $25)