What is Colorado's income tax rate on self-employment income in 2026?

Colorado uses a flat 4.25% individual income tax rate for 2026, applied to federal taxable income with small state adjustments.

Do Colorado freelancers pay state quarterly estimates?

Yes, if you expect to owe $1,000 or more of Colorado tax. Pay via Revenue Online or Form DR 0104EP on the same four dates as federal 1040-ES.

What is the Denver occupational privilege tax?

Denver charges a $5.75 per month occupational privilege tax on anyone who earns $500 or more working in Denver, including self-employed 1099 workers, who must file and pay it themselves. Aurora, Glendale, Greenwood Village and Sheridan have similar OPTs.

How much should a Colorado gig worker set aside for taxes?

Most Colorado gig workers land between 24% and 30% of net profit once federal income tax, 15.3% SE tax and the 4.25% state tax are combined.

Is mileage deductible on the Colorado return?

Yes. Colorado starts from federal taxable income, so the $0.70 per business mile 2026 standard mileage rate reduces your state tax automatically.

Does Colorado Springs or Boulder tax gig income locally?

No. Outside the OPT cities, Colorado municipalities do not tax personal income. Sales tax licenses matter only if you sell taxable goods.

Colorado Self-Employed Tax Calculator

Federal + 15.3% SE + Colorado flat 4.25% state income tax on 2026 1099 income, with notes on Denver's occupational privilege tax.

Colorado keeps the state side simple with a flat 4.25% on taxable income, and because it starts from federal taxable income, your mileage and expense deductions carry straight through. The local quirk is the occupational privilege tax: Denver, Aurora and a few other Front Range cities charge a small monthly OPT on work performed there, and as a 1099 worker you file it yourself.

Self-employed income & expenses

Estimate federal + SE + state tax for the 2026 tax year in one pass.

Annual 1099 income

Business miles driven

Other business expenses

Self-employed health insurance

Retirement contributions (SEP / Solo 401k)

W-2 income (if any)

Federal tax withheld

Filing status

State

Estimated total tax bill

$12,355

Refund / owed

-$12,355

Effective rate

20.6%

Detailed breakdown

Mileage deduction$5,600

Total business expenses$8,100

Net self-employment income$51,900

Self-employment tax (15.3%)$7,333

½ SE deduction (above-the-line)$3,667

Adjusted gross income$48,233

Taxable income$32,133

Federal income tax$3,608

State tax (est.)$1,414

Quarterly estimated payment$2,919

Marginal rate16.4%

Colorado city tax rates for self-employed workers (2026)

Colorado taxes income at a flat state rate and, unlike most states, several Front Range cities withhold their own local taxes on work performed there — Denver, Aurora, Glendale, Greenwood Village and Sheridan levy an occupational privilege tax.

Local and state tax rates for self-employed residents of major Colorado cities in 2026
City	Local rate	State rate	What gig workers should know
Denver	$5.75/month occupational privilege tax	4.25% flat (2026)	OPT applies when you earn $500+ in a month working in Denver, even as a 1099 contractor; employers usually remit it, self-employed file themselves.
Aurora	$2/month occupational privilege tax	4.25% flat	Applies to work performed in Aurora; self-employed file Form OPT directly.
Colorado Springs	No local income tax; sales tax license if selling goods	4.25% flat	No OPT; city use tax matters only for resale or goods sellers.
Boulder	No income tax; city sales/use tax license	4.25% flat	Separate Boulder sales tax return for taxable sales; none for pure service gig work.
Fort Collins	No local income tax	4.25% flat	State flat tax only; sales tax license only for taxable goods.

Colorado local and state filing deadlines

Q1 CO estimated paymentApril 15, 2026
Required if you expect to owe $1,000 or more of Colorado tax; pay via Revenue Online or Form DR 0104EP.
Q2 CO estimated paymentJune 15, 2026
Second state installment.
Q3 CO estimated paymentSeptember 15, 2026
Third state installment.
Q4 CO estimated paymentJanuary 15, 2027
Final installment for the 2026 year.
CO Form 104 returnApril 15, 2027
Automatic extension to October 15, 2027 to file, not to pay.
Denver OPT filingQuarterly or annually (by account)
Self-employed workers in Denver file their own occupational privilege tax returns.
Q1 federal 1040-ESApril 15, 2026
Covers income earned January 1 – March 31.
Q2 federal 1040-ESJune 15, 2026
Covers April 1 – May 31.
Q3 federal 1040-ESSeptember 15, 2026
Covers June 1 – August 31.
Q4 federal 1040-ESJanuary 15, 2027
Covers September 1 – December 31.

Colorado starts from federal taxable income, so mileage at $0.70 per business mile for 2026 flows straight through to your state return.
The occupational privilege tax is based on where you work, not where you live — track which city your gigs ran in.

Frequently asked questions

What is Colorado's income tax rate on self-employment income in 2026?: Colorado uses a flat 4.25% individual income tax rate for 2026, applied to federal taxable income with small state adjustments.
Do Colorado freelancers pay state quarterly estimates?: Yes, if you expect to owe $1,000 or more of Colorado tax. Pay via Revenue Online or Form DR 0104EP on the same four dates as federal 1040-ES.
What is the Denver occupational privilege tax?: Denver charges a $5.75 per month occupational privilege tax on anyone who earns $500 or more working in Denver, including self-employed 1099 workers, who must file and pay it themselves. Aurora, Glendale, Greenwood Village and Sheridan have similar OPTs.
How much should a Colorado gig worker set aside for taxes?: Most Colorado gig workers land between 24% and 30% of net profit once federal income tax, 15.3% SE tax and the 4.25% state tax are combined.
Is mileage deductible on the Colorado return?: Yes. Colorado starts from federal taxable income, so the $0.70 per business mile 2026 standard mileage rate reduces your state tax automatically.
Does Colorado Springs or Boulder tax gig income locally?: No. Outside the OPT cities, Colorado municipalities do not tax personal income. Sales tax licenses matter only if you sell taxable goods.