Formed in 2005 in Los Angeles, CA, +44 is a band from two former Blink-182 members Mark Hoppus (Bass Guitar/Vocals) and Travis Barker (Drums/Keyboards), who has also played in a variety of musical projects including The Aquabats, Box Car Racer, and Transplants. +44 also features Shane Gallagher (Lead Guitar), from The Nervous Return, and Craig Fairbaugh (Rhythm Guitar/Backing Vocals), from Lars Frederiksen and the Bastards, The Forgotten, and Mercy Killers.

It also once featured Carol Heller (Guitar/Backing Vocals), formerly of Get the Girl, but she later left the band to start a family. She is heard as backup vocalist in 3 of the tracks on the first album. The name +44 is a reference to the international dialing code for the United Kingdom, where Hoppus and Barker first discussed the new project.

On December 13th, 2005 (Tom Delonge's birthday), the band released a demo of the song "No It Isn't". Hoppus insists that, while it was directed towards Delonge's breaking up of blink-182, the release date was just coincidental. On September 1st 2006, they added a song called "Lycanthrope" to their official website, http://www.plusfortyfour.com. Also on September 7th, the +44 Song "When Your Heart Stops Beating" was played on KROQ radio. On September 18th, an unedited version of the song was posted on the band's MySpace profile.

Their debut album "When Your Heart Stops Beating" was released on November 14, 2006.

Hoppus has stated that the songs "Little Death" and "No It Isn't" are about the break-up of blink-182. In both songs lines such as "Your cry for inspiration won't be heard on distant stars" or "you swore you wouldn't lose then lost your brain, you make a sound that feels like pain" can be seen to be related to Angels and Airwaves, DeLonges new project.

In several interviews Hoppus has claimed Tom quit the band through his agent and didnt even bother to call Hoppus or Barker.

While shooting the video for the first Single "When your Heart stops beating" Travis Barker broke his arm. Not noticing it was broken he played an entire Europe-Tour with the arm broken.

On their recent European tour, fresh from his arm recovery, Travis had to go home early as his arm had got worse, though the tour has continued with his replacement drummer being Gil Sharone of Stolen Babies.

Some people may find a song on P2P networks called "We Know The Way" improperly credited to +44. The Song is actually by british band Page 44