ET sat down with the 34-year-old singer on Friday, where she revealed that her level of confidence has risen exponentially since welcoming 2-year-old daughter River Rose and 7-month-old Remington Alexander.
"I have never been more confident as a woman as I am as a mother," she said. " I feel like I am nailing it."
Clarkson, who is also step-mom to husband Brandon Blackstock's two children from a previous relationship, Seth and Savannah, said it takes "a lot" to manage her family's busy schedules, but she loves doing it.
"We have a blended family that is another level of trying to make it work and everyone feeling as equally loved and important," she explained. "And then also just having a marriage and having a career and having everything. It is a lot."
"I am more confident now because of all these things my life now entails," she added. "And when you are put in charge of someone not only as a business -- I employ a lot of people -- but also there are four lives I am a part of molding, and that is a big responsibility. And with that responsibility, I feel like it kind of brings this different level of like, 'I’ve got this. I might cry my way through this, this morning but I am going to make it and it is going to be good in the end.'"
The singer has a completely different life now than she did when she first won American Idol in 2002, but she wouldn't change it for anything.
"The Kelly now and the Kelly of my 20s, that is the difference between selfish and selfless," she said. "Because when you are 20 you are supposed to be a little selfish and do all your drama. And then in your 30s you have get [your life] a little more together…Priorities change."
"I used to [think] everything was so important with work," she explained. "And it is still important, but I am not a brain surgeon so no one is dying on a table if I do not record a song. It is OK if I go to art class with my daughter instead."
Spending time with her children and making sure they're raised with the right values is something that is important for Clarkson, and she says is one of the reasons she started her holiday charity benefit concert, Miracle on Broadway.
"I think Miracle on Broadway came about because I have always done stuff in my career throughout the year or especially at Christmas to help give back, but I wanted to do it in a way too that it was kind of [focused on] family," she shared.
"[My husband and I] grew up very differently than our children are growing up, and our children are growing up very differently than the average child, so it is very important for us to show them how important events like this are," Clarkson added, "and how important it is to realize [that] we are super fortunate."
"It's certainly hard to show them the gravity of certain situations because of their upbringing, but it's very important to my husband and me to make sure that impact is happening because you don't want some kind of snot kid running around not knowing the difference," she said.
Clarkson and a few famous friends will gather for her Miracle on Broadway benefit concert in Nashville, Tennessee on Dec. 16.