Spending was up at least 6.5% from the $12.4 billion spent on the same day last year, according to Adobe Analytics, a San Jose, California-based software company.

Sales are expected to reach between $13.2 billion and $13.5 billion by midnight on Monday. That would make it the biggest shopping day of the year -- and of all time.

Consumers nabbed steep holiday discounts on everything from electronics to toys following lackluster demand at US stores on Black Friday.