Enterprise
Individual & Small Business
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Federal 2026 estimated tax due dates, for comparison: April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027.
Who must pay Colorado estimated tax?
In most cases, you must pay estimated tax if you expect to owe more than $1,000 in net tax for the year, after subtracting any withholding or credits you might have. (Text from 2025 DR 0104EP; 2026 edition not retrievable.)
How do you avoid a Colorado underpayment penalty?
Required annual payment is the smaller of: 70% of the actual net Colorado tax liability; 100% of the preceding year's net Colorado liability (only if the preceding year was a 12-month year, a Colorado return was filed, and federal AGI on that return was $150,000 or less ($75,000 MFS)); or 110% of the preceding year's net Colorado liability (12-month year, Colorado return filed). Farmers/fishermen (2/3 of income): 50% of actual liability.
How much should you pay?
Start with your federal estimate: the free Quarterly Estimated Tax Calculator works out your 2026 federal payments and safe harbor. Colorado figures its own tax, so the state amount is separate.