"It was just a really emotional decision."
Kim has already asked to keep her personalised microphone pack as a memento.
She quipped: "Whoever thought we'd miss getting mic'ed?"
The Skims founder - who has North, seven, Saint, four, Chicago, two, and 16-month-old Psalm with husband Kanye West -insisted it was the right time to end the show because her family are all in need of a "break" and want to be there for their kids.
She said: "This was a dream of all of ours.
"We never imagined we would get onto season two. Now we're on 20. Sometimes we just need a break. It's really simple. We just need a minute to regroup."
"You know, we haven't had a break for 14 years. We've gone in filming a season, then a spin-off and I think there's no other way to say it other than, we just live such big lives. And we have kids now. And they need us."
"There's so much going on that, even just for a minute we need a break."
Kim has promised the final season of the show will reveal a whole new side to the clan because it will chronicle how they coped with the coronavirus pandemic and being in lockdown.
She said: "If anything, it'll be really interesting to see what all of us were doing during the pandemic. We were so scared and cautious and we shared every moment of that.
"Having to be with four kids and not have their friends or their routines and no help. It was a very different side of us that I don't think anyone's really seen."
The season will begin with footage they shot themselves on their phones, but filming is now up and running properly.
Kim said: "Now the production can happen, in a very careful way, but the end of the season goes back into a little bit of normalcy. We want to fully live this out."
