Colorado Quarterly Tax Payments: Due Dates, DR 0104EP, and Safe Harbors

If you earn income in Colorado that isn’t subject to withholding, you generally owe Colorado quarterly tax payments whenever your net state tax after credits will be $1,000 or more for the year.¹ The four installments are due April 15, June 15, September 15, and January 15 of the following year, and you send them using Form DR 0104EP or through the state’s Revenue Online portal.²

Who Owes Estimated Tax in Colorado

The rule turns on a single number. If your Colorado income tax for the year, after subtracting allowable credits but before counting any withholding or estimated payments, will be $1,000 or more, you owe estimated tax.¹ This most often catches freelancers, independent contractors, small business owners, landlords, and people with significant investment income.

Having a W-2 job doesn’t automatically exempt you. If side income pushes your total liability more than $1,000 above what your employer withholds, you owe estimated payments on the gap. Some people prefer to raise their W-2 withholding instead so they don’t have to track quarterly vouchers.

Joint filers apply the $1,000 threshold to their combined liability, and if you file joint federal estimated tax you must also file joint Colorado estimated tax.³

Quarterly Due Dates

Colorado splits the tax year into four installment periods:²

First quarter: April 15
Second quarter: June 15
Third quarter: September 15
Fourth quarter: January 15 of the following year

When a due date falls on a weekend or state holiday, it rolls to the next business day. If you mail your payment, the U.S. Postal Service postmark is what counts. A payment postmarked on or before the deadline is timely even if it arrives later; a postmark after the deadline is late.⁴

Each installment is expected to be one-quarter of your required annual payment. The state assesses penalties based on cumulative underpayment at each date, so paying somewhat more in one quarter and less in another doesn’t automatically trigger a penalty.

Safe Harbors That Prevent a Penalty

Colorado gives you three ways to avoid an underpayment penalty. Your required annual payment is the smallest amount produced by any of these options, and hitting it protects you even if you end up owing more at filing:

70% of your current year’s actual Colorado tax.⁵
100% of your prior year’s net Colorado tax, available only if last year was a full 12-month year, you filed a Colorado return, and your federal adjusted gross income was $150,000 or less ($75,000 or less if married filing separately).⁵
110% of your prior year’s net Colorado tax, if your prior-year federal AGI exceeded $150,000, again requiring a full 12-month prior year.¹

Most self-employed taxpayers with reasonably steady income find the prior-year method simpler, because it locks in a known number and doesn’t require projecting the current year.

Calculating Each Payment

Colorado applies a flat 4.40% rate to state taxable income, which starts from your federal taxable income and is adjusted for Colorado-specific additions and subtractions.⁶⁷

A quick example: if you expect $80,000 of Colorado taxable income, your annual state tax comes to $80,000 × 0.044, or $3,520. Divide by four and each quarterly payment is $880. The DR 0104EP form includes a worksheet that walks through this in more detail, factoring in credits and any withholding already paid on your behalf.

What matters for the penalty is net tax after credits. If credits and withholding together bring your remaining liability below $1,000, you don’t need to send estimated payments at all.

When Your Income Isn’t Steady

Equal quarterly payments don’t fit every taxpayer. If most of your income arrives late in the year, Colorado lets you use the annualized income installment method, which sizes each payment to the income you’ve actually earned through the end of the month before the due date. You can only use this method for Colorado if you also elected it federally, and the applicable percentages are 17.5%, 35%, 52.5%, and 70% of annualized tax at the four due dates.⁵ Keep records of how you allocated income; the Department of Revenue can ask for them.

Filing the DR 0104EP

The form for individual estimated payments is the DR 0104EP.⁸ The Department publishes an updated version each year, so use the one that matches the tax year you’re paying for.

The voucher asks for your Social Security Number or ITIN, name, address, and payment amount. If you file jointly, use the same name and SSN that will appear first on your annual return.⁹

How to Pay

The fastest option is Revenue Online at Colorado.gov/RevenueOnline. Electronic funds transfer and e-check carry no fee. Credit and debit cards add a convenience fee of (payment amount + $0.75) × 2.25%, which on a $3,000 payment works out to roughly $67.50.¹⁰ Online payments generate an immediate confirmation number; save it with your records.

To pay by mail, send your check or money order with the completed DR 0104EP voucher to:²

Colorado Department of Revenue
Denver, CO 80261-0008

Make the check payable to “Colorado Department of Revenue” and write your Social Security number, the tax year, and “Form DR 0104EP” on it. Don’t send a check without the voucher. A trackable mailing method gives you proof of timely submission if the envelope is lost.

What Underpayment Costs

Missing every safe harbor doesn’t trigger a flat penalty. Instead, Colorado charges interest on the shortfall for each quarter, calculated based on how much you underpaid and how many days passed between the installment due date and when you eventually paid or filed. For 2026 the rate on estimated tax underpayments is 8% annually, and interest compounds daily with no cap.¹¹

Colorado uses Form DR 0204 to compute the amount owed, which you file with your annual return when a shortfall exists.¹² Because the calculation runs quarter by quarter, getting close to a safe harbor still limits your exposure. A $500 shortfall for one quarter costs far less than skipping every payment on a $10,000 liability.

If You Overpay

Overpaying isn’t harmful, but your money is tied up until you file. You can’t request a mid-year refund on estimated payments. At filing time you choose whether to take the overpayment as a refund or apply it as a credit toward the following year’s first installment. A designated carryforward posts automatically to that first quarter.

Farmers and Fishermen

If at least two-thirds of your gross income comes from farming or fishing, you get a simpler schedule. You can make one estimated payment by January 15 of the following tax year instead of four, or skip estimated payments entirely by filing your Colorado return and paying the full balance by March 1.⁵ Meeting the March 1 deadline eliminates any underpayment penalty for the year.

A Note on Businesses

The rules above cover individual taxpayers, including sole proprietors, partners, and S corporation shareholders, whose business income flows to a personal return. C corporations follow separate rules, use Form DR 0112EP, have a $5,000 threshold, and pay their fourth installment on December 15 rather than January 15.¹³

1
Colorado Public Law. Colorado Code CRS 39-22-605 – Failure by Individual to Pay Estimated Income Tax
2
Department of Revenue – Taxation. Individual Income Tax – Estimated Payments
3
Colorado Department of Revenue. Estimated Income Tax
4
Colorado Department of Revenue. Regulation 39-21-119 – Date Document or Payment Considered Made
5
Legal Information Institute. 39-22-605 – Estimated Individual Income Tax
6
Department of Revenue – Taxation. Individual Income Tax – Frequently Asked Questions
7
Colorado General Assembly. Individual Income Tax
8
Department of Revenue – Taxation. DR 0104EP – Individual Estimated Income Tax Payment Form
9
Colorado Department of Revenue. Individual Estimated Income Tax Payment Form
10
Colorado Department of Revenue. Payment Frequently Asked Questions
11
Department of Revenue – Taxation. Tax Topics – Penalties and Interest
12
Colorado Department of Revenue. Computation of Penalty Due Based on Underpayment of Colorado Individual Estimated Tax
13
Department of Revenue – Taxation. Business Income Tax – Estimated Payments