In Colorado, the penalty for late filing state taxes depends on the amount of tax owed and the duration of the delay. The late filing penalty is generally 5% of the tax due for each month or part of a month that the return is late, up to a maximum of 12 months. Additionally, interest is charged on the unpaid tax amount at the rate published by the Colorado Department of Revenue. It is important to note that penalties and interest for late filing can vary based on individual circumstances, so it is best to refer to the official Colorado Department of Revenue guidelines or consult a tax professional for accurate and specific information.