Walmart rolled out free next-day shipping in Philadelphia and area counties this week, positioning the retail giant to compete with Amazon on quick delivery.

The Bentonville, Ark., company said its plans for next-day delivery to reach about 75 percent of the U.S. population by the end of the year, with shoppers being able to choose from nearly 220,000 items on Walmart.com.

Amazon’s staple, free two-day shipping for Prime members, has evolved into a same-day model, but it remains unclear if the difference between same-day, one-day, or two-day shipping will be a significant factor for shoppers choosing among Walmart, Amazon, and other retailers.

Shoppers don’t seem to care “as much as retailers think,” Sucharita Kodali, an analyst for Forrester, wrote in an April blog post. She said more than half of shoppers surveyed by Forrester said free shipping “was a big driver,” but 8 percent called expedited shopping “important for them.”

“Better prices, not shipping options, was the top reason for purchasing on Amazon specifically,” she wrote.

To find out whether your Walmart order qualifies for free next-day delivery, open Walmart’s website and slide the bar on the top left of the page to “NextDay delivery.” There are zip codes in Montgomery, Bucks, Chester, Delaware, Burlington, Camden, and Gloucester Counties that qualify, with more rolling out, the company said. The delivery is available for orders of at least $35, the company said.

Walmart reported that its total revenue for the first quarter — the 13 weeks ending April 26 — came to $123.9 billion, a 1 percent increase. Walmart U.S. same-store sales rose 3.4 percent and e-commerce sales grew 37 percent, the company announced.

“We’re changing to enable more innovation, speed, and productivity, and we’re seeing it in our results,” Doug McMillon, Walmart’s chief executive officer, said in a news release. “Our team is demonstrating an ability to serve customers today while building new capabilities for the future, and I want to thank our associates for a strong start to the year.”