The average cost of a wedding in the United States is $35,329, according to the popular wedding website, The Knot, which polled around 13,000 brides. But it's also really expensive to be wedding guest anymore, and that's leading many people — especially millennials — to stay home on the big day.

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How much does it typically cost to be a wedding guest?

MarketWatch, reporting on a survey by the travel website Priceline that sampled 1,016 adults over age 2 found that it costs "upwards of $600" per "wedding event."

That means: not just the wedding, but the bachelor/bachelorette party, the engagement party, engagement party, and bridal shower. It adds up.

Additionally, there are gifts to buy and, sometimes, plane tickets to book, as well as hotel rooms. Of those surveyed, 38 percent said it's the accommodations that cost the most, "especially if the wedding is in a hot spot like New York or San Francisco," Brides reports.

It's these costs that explain why about 40 percent of guests now opt not to attend a wedding, according to MarketWatch. And as The Cut noted, the wedding sometimes isn't the only destination event to plan for.

It's become increasingly common for bachelor and bachelorette parties to take place in a separate location (53 percent of those surveyed said that was their experience). Of those who attend, 24 percent said they spent "at least $800 to $1,000" for those pre-wedding events.

This isn't just whining from a handful of young adults.

If you search "I can't afford to go to wedding" on Google, you will find millions of results:

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As Lisa Bonos of The Washington Post explained, "I accept more out-of-town wedding invitations than I turn down. If I can make it work with my schedule and my bank account, I like to celebrate my friends. [...] But sometimes it’s just too much time and money to attend."

Bonos said she spoke to financial planners who revealed "they had seen people go into debt over attending friends’ weddings."

Millennials aren't broke because they're not working hard.

As USA Today reported in Jan. 2017, "a new Federal Reserve report shows millennials making 20 percent less than their parents [when they were their age]." Additionally, "millennials have half the net worth of boomer," on top of larger student loan debts. 

A Practical Wedding, a wedding site made by and for millennials, published a piece last year titled, "Student Debt Is Going to Be a Huge Problem for Millennial Marriages." Now it's clear money and debt are big problems for the guests too.