Amazon touts 'biggest ever' Prime Day as U.S. online sales surge to $12.7 billion

Online spending in the U.S. climbed 6.1% to $12.7 billion during Amazon's Prime Day promotion, according to Adobe Analytics, as deal-hungry consumers snapped up home goods and household essentials.

Amazon called the event its "biggest ever" Prime Day, with shoppers buying more than 375 million items worldwide over two days, up from 300 million items sold last year, the company said Thursday.

The 48-hour sales event kicked off Tuesday and ran through Wednesday. Amazon, which didn't disclose total sales from the event, said the first 24 hours of Prime Day marked the "single largest sales day in company history."

Home goods, fashion, and beauty were among the top categories during the discount bonanza, while shoppers scooped up Fire TV sticks, Apple AirPods, and Laneige lip balm, the company said. Adobe also highlighted appliances, housekeeping products and office supplies as popular categories, while some of the deepest discounts were on electronics, apparel and toys.

Amazon started Prime Day in 2015 to lure new Prime subscribers and deepen existing members' loyalty to the program, as well as drum up sales during the slower summer months. The company typically uses the event to promote and discount Amazon-branded devices like its Echo smart speakers and Fire tablets.

Despite the strong showing, which Adobe said set "a new record for Prime Day," the results still fell short of expectations. Adobe had forecast total U.S. online sales to grow 9.5% year over year to $13.1 billion during the two-day event. Last year, U.S. consumers spent more than $11.9 billion.

Rival retailers including Walmart, Target, Best Buy and Kohl's hosted competing discount events alongside Prime Day.

Preliminary shopping data from the event indicates that consumer spending may be stronger than feared in the face of economic uncertainty and still-high inflation. Shoppers spent more per order, with an average order size of $54.05, up from $52.26 during last year's event, according to Numerator data as of Thursday morning.

Roughly 52% of the more than 1 million households surveyed by Numerator said they purchased items during Prime Day they'd been holding off on buying until they were on sale.

WATCH: Consumer feeling stretched and looking for deals during Amazon Prime Day