To file sales tax in Colorado, submit Form DR 0100 through the Department of Revenue’s Revenue Online portal by the 20th of the month after your reporting period ends, reporting gross sales, exempt sales, and taxable sales broken out by each jurisdiction where you did business. Every licensed retailer files on this schedule, and a return is due for every period even when no sales occurred and no tax is owed.1Department of Revenue – Taxation. Sales Tax Filing Information
Your Filing Frequency and Deadline
How often you file depends on how much state sales tax you collect. Monthly is the default. Businesses whose average monthly collections run under $300 can generally be approved to file quarterly, and businesses collecting less than $15 per month can request annual filing if monthly or quarterly would be an unnecessary burden. The Department monitors your volume and can shift you to a different frequency as sales grow or shrink.2Cornell Law Institute. Colorado Regulation 39-26-109 – Sales Tax Filing Schedules
The deadlines share the same pattern regardless of frequency:
- Monthly filers: the 20th of the month after the reporting period.
- Quarterly filers: April 20, July 20, October 20, and January 20.
- Annual filers: January 20 of the following year.
When the 20th lands on a weekend or holiday, the deadline shifts to the next business day.1Department of Revenue – Taxation. Sales Tax Filing Information
What You Need Before You File
Have three numbers ready for the reporting period: gross sales, exempt sales, and the net taxable amount that results when you subtract the second from the first.3Colorado Department of Revenue. DR 0100 – Colorado Retail Sales Tax Return
Gross sales are the total value of everything you sold before any deductions. Exempt sales are the transactions that qualify to come out: wholesale sales backed by a resale certificate, sales to government agencies, and out-of-state deliveries are common examples. What remains is your net taxable amount, and you multiply it by the applicable tax rate to get the tax due.4Department of Revenue – Taxation. DR 0100 – Retail Sales Tax Return
You also need your sales broken out by location. Because state-administered local taxes ride on the DR 0100, you have to allocate sales to each jurisdiction where you had activity. A miscoded jurisdiction sends revenue to the wrong local government, and you can end up owing the correct one separately.
Keep your eight-digit Colorado Account Number handy. It goes on the return and on any payment you send.
Where to File the Return
Most businesses file through Revenue Online, the Department’s digital portal. After logging in, you select the tax year and filing period, then enter your sales data. Larger datasets can be uploaded from a spreadsheet. Businesses with multiple locations must file a separate return for each location or use approved sales tax software to file in bulk.5Department of Revenue – Taxation. File Sales Tax on Revenue Online
Electronic filing isn’t legally required. If you can’t file online, download a paper DR 0100 from the Department’s website and mail it in.
Using SUTS for Multiple Jurisdictions
The Sales and Use Tax System (SUTS) is a separate portal built to reduce the pain of filing across multiple local jurisdictions. SUTS lets you look up tax rates by address, file returns, and remit payments to participating jurisdictions in one session.6Department of Revenue – Taxation. Colorado Department of Revenue’s New, Improved System Speeds Sales Use Tax Filing Not every home-rule city participates. The Department publishes a list of participating jurisdictions, along with contact information for self-collecting cities, in its DR 1002 publication.7Department of Revenue – Taxation. SUTS Participating Jurisdictions
Paying and Confirming
Payment options are built into both online portals. You can pay by Electronic Funds Transfer (EFT), credit or debit card, or e-check. Checks and money orders are accepted too, but you must write your eight-digit Colorado Account Number on the payment. Leaving it off delays processing and can trigger a balance-due letter. If you’re paying a tax bill rather than remitting with a regular return, use the payment voucher that came with your Statement of Account.8Department of Revenue – Taxation. Pay Sales and Use Tax
After you submit, the system generates a confirmation number. Save it. That number is your proof of filing if a dispute comes up later. Electronic payments typically clear within two to five business days, and you can track status through your Revenue Online account history.
Claim the Vendor Discount
Colorado gives you a small credit for the work of collecting and remitting. You can retain 4% of the state sales tax you report, up to $1,000 per filing period.9Justia Law. Colorado Code 39-26-105 – Vendor Liable for Tax File or pay late and you lose it for that period, which is a real cost stacked on top of any penalty.10Department of Revenue – Taxation. Tax Topics – Penalties and Interest
Penalties for Filing Late
Skip a return and the Department doesn’t wait. It files an estimated return on your behalf and bills you for the estimate, which stays on the books until you submit an actual return.1Department of Revenue – Taxation. Sales Tax Filing Information
The penalty for failing to file, pay, or correctly report is the greater of $15 or 10% of the unpaid tax, plus 0.5% for each additional month the balance sits unpaid, capped at 18% of the unpaid amount. Interest accrues on top. For 2026, the discounted interest rate is 8% if you pay before or within 30 days of a notice of deficiency; miss that window and the rate goes to 11%. Late payment also forfeits the vendor discount for that period.10Department of Revenue – Taxation. Tax Topics – Penalties and Interest
A single late month is manageable. The real damage comes from letting several periods stack, because the percentage-based penalties and interest compound across each missed return.
Filing in Home-Rule Cities
Filing the DR 0100 does not cover everything. Colorado has dozens of home-rule cities that collect their own sales tax independently, set their own rates, define their own taxable goods and services, and require separate registration and filing. If you sell into one of these cities and it doesn’t participate in SUTS, you have to register with the city directly and file a separate return on its schedule.11Department of Revenue – Taxation. Local Government Sales Tax Missing that obligation generates penalties from the city independently of anything the state does.
Zero Returns and Amended Returns
A return is due for every reporting period even when you had no sales and owe no tax. File a zero return through Revenue Online on the normal schedule to keep your account in good standing.1Department of Revenue – Taxation. Sales Tax Filing Information
If you find an error after submitting, file an amended DR 0100 through Revenue Online. An amended return replaces the original entirely, so you enter the full corrected figures for the period, not just the difference.4Department of Revenue – Taxation. DR 0100 – Retail Sales Tax Return If the corrected numbers show underpayment, you owe the difference plus interest. If you overpaid, request a refund through the same process. Don’t sit on known errors; the Department assesses penalties from the original due date, so the sooner you amend, the less interest builds.