Is $400 your total income for the year, or is that just the amount you made in Colorado? Were you paid the $400 as and employee (you got a W-2), or as an independent contractor?
You are required to file a Colorado return if you are required to file a federal return and you have any Colorado income at all, no matter how little.
If you made $400 or more as an independent contractor (also called self-employed or in business for yourself) you are required to file a federal return, even if you had no other income.
If you were a W-2 employee, whether you are required to file a federal return depends on a number of factors. You can use the tool at the following link on the IRS web site to find out if you are required to file.
<a rel="nofollow" target="_blank" href="
https://www.irs.gov/uac/do-i-need-to-file-a-tax-return">https://www.irs.gov/uac/do-i-need-to-file-a-...>
