Quick Answer
Increase your W-4 withholding by having extra tax withheld from each paycheck. If your side hustle generates $5,000 profit and you're in the 22% tax bracket, have an additional $77 per paycheck withheld ($5,000 × 15.3% SE tax + 22% income tax = $1,865 ÷ 26 paychecks).
Best Answer
James Okafor, Self-Employment Tax Specialist
People earning regular W-2 income who also have freelance or side business income
How to calculate extra withholding for side hustle income
The easiest way to cover side hustle taxes is through extra W-4 withholding rather than quarterly payments. You'll need to calculate both the income tax and self-employment tax on your side hustle profit, then divide by your number of paychecks.
Here's the formula:
Example: $8,000 side hustle profit, 22% tax bracket
Let's say you earn $65,000 from your W-2 job and expect $8,000 profit from your side hustle this year. You're paid biweekly (26 paychecks).
Calculate additional taxes needed:
How to adjust your W-4:
1. Complete a new Form W-4
2. On line 4(c), enter $115 as "Extra withholding per pay period"
3. Submit to your employer's payroll department
4. Your next paycheck will have $115 less take-home pay
When this strategy works best
Good candidates for W-4 adjustment:
Consider quarterly payments instead if:
Key factors that affect your calculation
What you should do
Use our quarterly estimator tool to calculate exactly how much extra withholding you need based on your specific situation. The tool accounts for your current withholding, expected side hustle income, and tax brackets to give you the precise amount for line 4(c) of your W-4.
Key takeaway: For most people earning under $15,000 in side hustle profit, adjusting W-4 withholding is simpler than making quarterly payments. Calculate 15.3% for SE tax plus your marginal rate for income tax, then divide by your pay periods.
*Sources: [IRS Publication 505](https://www.irs.gov/pub/irs-pdf/p505.pdf), [IRS Form W-4](https://www.irs.gov/pub/irs-pdf/fw4.pdf)*
Key Takeaway: Adjust your W-4 to withhold an extra amount equal to your side hustle profit times your combined tax rate (15.3% SE tax + your income tax rate), divided by your number of paychecks.
Comparing W-4 withholding vs quarterly payments for different side hustle income levels
| Side Hustle Profit | Annual Tax Owed | W-4 Extra Per Paycheck (26 pays) | Quarterly Payment |
|---|---|---|---|
| $3,000 | ~$1,110 | $43 | $278 |
| $5,000 | ~$1,865 | $72 | $466 |
| $8,000 | ~$2,984 | $115 | $746 |
| $12,000 | ~$4,476 | $172 | $1,119 |
| $20,000 | ~$7,460 | $287 | $1,865 |
More Perspectives
Alex Torres, Gig Economy Tax Educator
People in their first year of freelance or side hustle income who are unfamiliar with tax obligations
Why W-4 adjustment might be perfect for your first year
As a new freelancer, you're probably feeling overwhelmed by the idea of quarterly estimated taxes. The good news? If you also have a W-2 job, you can often handle your side hustle taxes through payroll withholding instead.
Simple approach for beginners
Start with this rough calculation: take your expected side hustle profit and multiply by 35-40%. This covers both self-employment tax (15.3%) and federal income tax for most middle-income earners. Divide that number by how many paychecks you get per year.
Example for a $3,000 side hustle:
Common beginner mistakes to avoid
Track everything from day one
Whether you choose W-4 adjustment or quarterly payments, start tracking your side hustle income and expenses immediately. Use our freelance dashboard to categorize income by client and track deductible expenses. This makes tax time much easier and ensures you're calculating withholding on your actual profit, not gross income.
Key takeaway: For new freelancers earning under $10,000 in side income, W-4 adjustment is often easier than learning quarterly payments. Use 35-40% of your profit as a starting estimate.
Key Takeaway: New freelancers can simplify their first year by using W-4 withholding instead of quarterly payments, estimating about 35-40% of side hustle profit for total tax obligation.
James Okafor, Self-Employment Tax Specialist
Experienced workers who regularly balance both employment income and freelance projects
Strategic considerations for regular side hustlers
If you've been balancing W-2 and 1099 income for a while, you've probably experimented with both quarterly payments and W-4 adjustments. Here's how to decide which works better for your situation.
The cash flow advantage
W-4 withholding spreads your tax payments evenly throughout the year, which helps with budgeting. Instead of setting aside 25-35% of each side hustle payment, your regular paycheck handles it automatically.
Quarterly payments pros:
W-4 withholding pros:
When your side hustle income fluctuates
Many side hustlers have inconsistent income—busy months and slow months. W-4 withholding works well here because it averages out over the year. Calculate your expected annual side hustle profit, not your monthly average.
If your side hustle is very seasonal (like tax preparation or holiday crafts), consider a hybrid approach: increase W-4 withholding during your busy season, then reduce it during slow periods by filing a new W-4.
Advanced strategy: Safe harbor rule
If you paid at least 100% of last year's tax liability through withholding and quarterly payments combined (110% if your prior year AGI exceeded $150,000), you won't owe penalties even if your side hustle grows unexpectedly. This gives you flexibility to adjust your strategy mid-year.
Key takeaway: Experienced side hustlers benefit from W-4 withholding's consistency and automatic adjustment, especially when freelance income varies significantly month to month.
Key Takeaway: Regular side hustlers often prefer W-4 withholding for its consistency and automatic adjustment to income fluctuations, avoiding the complexity of quarterly payment timing.
Sources
- IRS Publication 505 — Tax Withholding and Estimated Tax
- IRS Form W-4 — Employee's Withholding Certificate
Related Questions
Reviewed by James Okafor, Self-Employment Tax Specialist on February 28, 2026
This content is for educational purposes only and is not a substitute for professional tax advice. Consult a qualified tax professional for advice specific to your situation.