Records show the 35-year-old undefeated champion is due for release Friday from the Clark County Detention Center.
Las Vegas police Officer Jose Hernandez said Wednesday that Mayweather was granted time off his 90-day sentence for work and good behaviour.
Mayweather surrendered for jail May 1 after pleading guilty in December to misdemeanour charges in a September 2010 scuffle with his girlfriend, Josie Harris, while two of their children watched.
The plea deal avoided a trial on felony charges that could have gotten Mayweather up to 34 years in prison.
Mayweather promoter Leonard Ellerbe didn't respond this week to messages.