CO — ColoradoColorado Personal Income Tax Extension — What You Need to Do
Colorado automatically extends your personal income tax filing deadline to October 15, 2026 — no form, no application, no federal extension required. The one catch that sets Colorado apart: to stay penalty-free, you must pay at least 90% of your Colorado tax by April 15. Miss that threshold and the late-payment penalty applies, even with the automatic extension in place.
Colorado Extension Checklist — 2026
Two things to handle. One payment threshold that matters.
Pay at Least 90% of Your Colorado Tax
Colorado’s extension covers filing — not payment. Pay at least 90% of your net Colorado tax by April 15 to avoid the late-payment penalty. Any remaining balance is charged interest only, and you can settle it when you file.
Revenue Online — EFT
colorado.gov/revenueonline
Free bank payment. EFT registration required in advance. No DR 0158-I needed.
Credit / Debit Card or E-Check
colorado.gov/revenueonline — pay as a guest, processing fee applies
File Federal + Colorado Return
File your federal return and add your Colorado return — Form DR 0104 — in the same session. Filing sooner means a faster refund. Your Colorado extended deadline is October 15.
Start Federal + Colorado Return →
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Colorado Late Payment Penalties — What It Costs to Wait
The extension gives you until October 15 to file. But if you pay less than 90% of your tax by April 15, penalties and interest start stacking on the unpaid balance.
| Penalty Type | Rate | Cap | Trigger |
|---|---|---|---|
| Failure to Pay | Greater of $5 or 5%, +0.5%/mo | 12% | Less than 90% paid by April 15 |
| Failure to File | Greater of $5 or 5%, +0.5%/mo | 12% | Filing after the October 15 extended deadline |
| Combined | — | 12% | Only the larger of the two penalties is assessed — they don’t stack |
| Interest | Accrues from April 15 | No cap | On any unpaid balance, including the remainder after paying 90% |
Colorado State Extension Details
| Extension Type | Automatic — Pay 90% by April 15 |
| Original Filing Deadline | April 15, 2026 |
| Extended Filing Deadline | October 15, 2026 |
| Extension Period | 6 months |
| Extension Form | None (automatic); DR 0158-I only to mail a payment |
| Return Form | DR 0104 (part-year / nonresident add DR 0104PN) |
| Federal Extension Required? | No — Colorado’s extension is independent |
| Payment Rule | Pay at least 90% of net tax by April 15 (remainder charged interest only) |
| Payment Deadline | April 15, 2026 (extension does not extend payment) |
| Online Payment Portal | colorado.gov/revenueonline |
| State Agency | Colorado Department of Revenue (CDOR) |
| Failure to File Penalty | Greater of $5 or 5% + 0.5%/mo, up to 12% |
| Failure to Pay Penalty | Greater of $5 or 5% + 0.5%/mo, up to 12% |
Colorado Tax Extension — Frequently Asked Questions
Do I need to do anything to get the Colorado extension?
No form or application — Colorado grants the 6-month extension automatically to every individual filer, moving your deadline to October 15, 2026. The only requirement is to pay at least 90% of your tax by April 15.
What is Colorado’s 90% payment rule?
To avoid the late-payment penalty, at least 90% of your net Colorado tax must be paid by April 15. The remaining balance (up to 10%) is charged interest only and can be paid when you file by October 15. Pay less than 90% and the penalty applies to the whole unpaid balance.
What is Form DR 0158-I — do I need it?
DR 0158-I is Colorado’s extension payment voucher, used only when mailing a check or money order. If you pay online at colorado.gov/revenueonline — or you owe nothing — you don’t need it.
Does the Colorado extension cover my federal return?
No. The Colorado extension only covers your state filing. Your federal return needs a separate extension (IRS Form 4868) if you want more time with the IRS.
What if I can’t pay my full Colorado tax by April 15?
Aim for at least 90% — that’s the threshold that keeps the late-payment penalty off. Below 90%, the penalty applies to the full unpaid balance, so every dollar toward that 90% matters.
How do I pay my Colorado extension online for free?
Use EFT (bank payment) through Revenue Online at colorado.gov/revenueonline — it’s free, though EFT registration is required in advance. Credit/debit card and e-check are also available as a guest, but a processing fee applies.
Ready to File? Start Federal + Colorado
File your federal return and add Colorado state in the same session. October 15 extended deadline — secure, fast, with live support.