Kris Jenner reveals how much Kardashians make per Instagram post

You might not think the Kardashians need to make any more money, but it would be hard to turn down six figures for an Instagram post.

Mother and 'momager' Kris Jenner revealed in an interview with CBS just how much her daughters are paid for advertising products online.

"My daughters are constantly getting offers to post something for a company, or a brand, on social media," the 63-year-old mogul said.

"They have a fee for a post, or a fee for a story, a fee for Facebook... they have a fee schedule."

When pressed on exactly how much they're paid per post, Jenner was a little more coy - but an endorsement from the world's most famous family doesn't come cheap.

"I mean, it's definitely six figures," she said. "Sometimes, if it's Kim, or if it's Kylie... it depends on what it really is," she went on, implying her two most famous children bring in the most dough.

Last year, Instagram scheduling software Hopper HQ estimated Kylie Jenner - who runs her own cosmetics company at just 21 - makes US$1 million (NZ$1.4 million) per sponsored post.

It estimated older sister Kim Kardashian is paid about US$750,000 (NZ$1.1 million) per post, while supermodel Kendall Jenner makes roughly US$500,000 (NZ$740,000).

Jenner explained that in the mysterious world of 'brand deals', pharmaceutical companies have to pay more for stars to advertise their products if they are intended to be drunk, ingested or otherwise put in or on the body.

Kim and Khloe Kardashian in particular have come under fire for endorsing weight loss products like appetite suppressant lollipops and 'flat tummy teas', which many have said promote unhealthy eating habits among their young female fans.

Instagram requires users to disclose when they've been paid to promote a product, although many influencers and celebrities don't bother including #ad in their captions.