The English star will play next season at the Emirates Stadium.
Ben White is undergoing his second medical to join Arsenal.
The English defender, who was included in England squad for Euro 2020, passed the first part of medical tests on Wednesday. Sky Sports now reports that Arsenal and Brighton have agreed a figure of £50 million. Earlier, Arsenal's offer of £40 million and £47 million was rejected.
also stipulate in the contract that if Arsenal sells White, part of the sales figure will go to the club.
White did not play for Gareth Southgate's side during Euro 2020 but played in two pre-tournament friendlies against Austria and Romania.
Brighton had the best defense in the bottom half of the Premier League table last season, conceding 46 goals, and White was one of the most effective players in that direction. The 23-year-old joined Brighton from Southampton in 2014 and played 41 games for the team. He played on loan for several teams and played a key role in Marcelo Bielsa and Leeds' return to the Premier League.