California Side Hustle Tax Guide 2025
Everything side hustlers in California (CA) need to know about taxes, deductions, and quarterly payments.
California Tax Overview
Highest state income tax in the US (up to 13.3%). Aggressive nexus rules — CA may tax you even after leaving if ties remain.
Your total tax burden includes federal income tax (10–37%), SE tax (15.3%), and California state tax (~9.3%).
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.
California 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 California tax side hustle income?
Yes, at ~9.3%. Federal SE tax (15.3%) always applies.
Do I need quarterly payments?
Yes, federal. State quarterly payments also required.
Occasional emails on systems, tax, and automation. No spam, unsubscribe anytime.
Free calculators — no signup, and the math runs in your browser.
See the calculators →