Kansas Statutes Chapter 16. Contracts and Promises § 16-201. Legal rate of interest

Creditors shall be allowed to receive interest at the rate of ten percent per annum, when no other rate of interest is agreed upon, for any money after it becomes due; for money lent or money due on settlement of account, from the day of liquidating the account and ascertaining the balance; for money received for the use of another and retained without the owner's knowledge of the receipt; for money due and withheld by an unreasonable and vexatious delay of payment or settlement of accounts; for all other money due and to become due for the forbearance of payment whereof an express promise to pay interest has been made; and for money due from corporations and individuals to their daily or monthly employees, from and after the end of each month, unless paid within fifteen days thereafter.