Montana’s income tax is a pay-as-you-go tax. You must pay your tax as you earn or receive income throughout the year.
There are two ways to pay your Montana income tax. Tax may be withheld from your income or you can pay estimated taxes.
This publication explains both of these methods. It also includes four worksheets you can use to determine the amount of estimated tax you may owe.
Download the Montana Publication 1 - Prepaying Income Tax