Colorado Side Hustle Tax Guide 2025
Everything side hustlers in Colorado (CO) need to know about taxes, deductions, and quarterly payments.
Colorado Tax Overview
Flat rate of 4.4%. Based on federal taxable income with state modifications. TABOR refunds may offset.
Your total tax burden includes federal income tax (10–37%), SE tax (15.3%), and Colorado state tax (~4.4%).
Self-Employment Tax
Every side hustler pays 15.3% SE tax on net earnings — 12.4% Social Security + 2.9% Medicare. You can deduct half from adjusted gross income.
Quarterly Estimated Payments
Federal quarterly payments required if you owe $1,000+ (Form 1040-ES). Due: April 15, June 15, September 15, January 15.
Colorado also requires quarterly state estimated payments.
Common Deductions
- Home office ($5/sq ft, max 300 sq ft)
- Equipment and software (Section 179)
- Vehicle (67¢/mile in 2024)
- Health insurance (self-employed deduction)
- Half of SE tax
- Retirement (SEP-IRA or Solo 401(k))
FAQ
Does Colorado tax side hustle income?
Yes, at ~4.4%. Federal SE tax (15.3%) always applies.
Do I need quarterly payments?
Yes, federal. State quarterly payments also required.
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