Back to school is a multi-billion-dollar industry — $40 billion, in fact, according to the Rubicon Project. Here’s how it all adds up.

COST PER STUDENT

Here’s a look at what parents expect to spend this school year on supplies, according to the Huntington Bank Backpack Index:

$658.82 — elementary school student

$956.77 — middle school student

$1,497.87 — high school student

TECH ON THE RISE

One of the big ticket items, of course, is tech. This year, parents plan to spend on average $505 on computers/laptops, tablets, phones or other mobile devices, according to the American Express Spending and Saving Tracker — up from $466 last year. That compares to $138 for school supplies. According to the study, 92% of parents reported that their children are using tech for learning, compared to 82% in 2015.

TEACHERS, TOO

Parents aren’t the only ones opening up their wallets. According to SheerID and Agile Education Marketing, K-12 teachers spent on average $487 of their own money on supplies for the 2015-16 school year.