Wal-Mart Stores Inc. plans to increase starting wages for its U.S. employees to at least $9 an hour, $1.75 above the federal minimum wage, beginning in April.

The pay raises are part of comprehensive changes to the company’s hiring, training, compensation and scheduling programs in the U.S., as well as to store management structure, Wal-Mart said Thursday. The estimated cost of the overhaul is more than $1 billion in the retailer’s current fiscal year, which began Feb. 1, the company said.

One of the initial changes is the raise in starting pay to at least $9 an hour this spring. All current associates will be paid at least $10 an hour by February 2016, the company said.

Wal-Mart said it also will be launching a program for future associates in which they will be paid $9 or more an hour next year, receive skills-based training for six months and then be guaranteed at least $10 an hour after completion of the program.

Wal-Mart, the world’s largest retailer, has been under intense pressure from organized labor groups to raise its starting hourly wage to $15 and provide workers with a more consistent work schedule. With its new changes, the company’s average full-time wage will be $13 an hour, up from $12.85, The Associated Press reported. For part-time workers, the hourly wage will be $10, up from $9.48, the AP said.

Wal-Mart said it expects 500,000 full-time and part-time employees at Wal-Mart stores and Sam’s Clubs in the U.S., nearly 40 percent of its 1.3 million U.S. employees, to benefit from the pay raises.

Chief Executive Doug McMillon said the changes “will give our U.S. associates the opportunity to earn higher pay and advance in their careers.”

The company also announced that starting next year it would offer some workers fixed schedules each week, and that employees would know their schedules at least 2½ weeks in advance.

Last year, rallies and marches were held nationwide as Wal-Mart workers and their supporters pushed for better wages and working conditions.

“We are so proud that by standing together we won raises for 500,000 Wal-Mart workers, whose families desperately need better pay and regular hours from the company we make billions for,” said Emily Wells, a leader of OUR Walmart, an organization of workers fighting for better wages and hours at the retailer.

However, Wells said the changes announced Thursday were not enough.

“Especially without a guarantee of getting regular hours, this announcement still falls short of what American workers need to support our families,” she said. “Wal-Mart can afford to provide the good jobs that Americans need – and that means $15 an hour, full-time, consistent hours and respect for our hard work.”