Texas Finance Code - FIN § 371.004. Computation of Month

(a) For the computation of time in this chapter, a month is the period from a date in a month to the corresponding date in the succeeding month. If the succeeding month does not have a corresponding date, the period ends on the last day of the succeeding month.

(b) For the computation of a fraction of a month, a day is equal to one-thirtieth of a month.