Montana Title 31. Credit Transactions and Relationships § 31-1-106. Legal interest

(1) Except as otherwise provided by the Uniform Commercial Code, 31-1-111, and 31-1-112, unless there is an express contract in writing fixing a different rate or a law or ordinance or resolution of a public body fixing a different rate on its obligations, interest is payable on all money at the rate of 10% a year after it becomes due on:

(2) In the computation of interest for a period of less than 1 year, 365 days constitute a year.