Top tournaments on the ATP Tour are to be expanded, with Masters events in Madrid, Rome and Shanghai set to increase to 12-day events from 2023.
Events in Canada and Cincinnati will also take place over 12 days, from 2025, as part of plans laid out by the governing body of the men's tour.
Prize money at the five expanded tournaments will grow by more than 35% by 2025, the ATP says.
Players and tournaments will share profits 50-50 from 2023.
ATP Masters tournaments in Indian Wells and Miami already take place as 12-day events with bigger draw sizes, while the four Grand Slams are played over two weeks - or 15 days in the case of the French Open.
"It helps tennis in general if the gap between Slams and Masters becomes a bit smaller because you want to have the continuity of the narrative," said ATP chairman Andrea Gaudenzi.
"That's a huge value, especially nowadays. Players like Apple, Amazon, Netflix - when they roll out a product, they roll it out in 180 markets not in one. What's better than tennis? It's 24-7, every day of the year, gender neutral, both men and women."
Closer integration between tennis' multiple governing bodies, including the women's WTA tour, is also planned, with Gaudenzi adding further collaboration between the men's and women's bodies is the "natural first step" in the next phase of the ATP's 'one vision' plan.