How to update W-4 to break even or get refund

[candace-p]

We're both W2 employees, but partner has a side gig/LLC and I also have "hobby income" from Amazon Vine

Wages are $90K+~$3K hobby, and $120K+~$15K from 1099, married filing joint

We will have 2 dependents for 2025, don't max 401k Roth contributions, but max HSA and Dependent Care Spending accounts.

I think I currently claim 1 dependent (2024), husband claims 0 and we do not withhold any extra $.  Do we need to? What is the optimal way to fill out our W-4s?  

[evelynm]

TurboTax has an amazing tax caster that will generate a new W-4 when you simply enter the numbers you indicated in your question along with your MFJ status and claiming the kiddos. 
Here is the link:  W-4 Tax Calculator 

Having multiple jobs can increase the likelihood of owing federal income tax at the end of the year. Here's why: 

1. Under-withholding:

• Each job assumes you have only one source of income. When you fill out your W-4 form for each job, they typically withhold taxes as if that were your sole income. This means that the tax withholdings may not be enough to cover your total tax liability from all sources of income. 
• Progressive tax system. The US uses a progressive tax system where your tax rate increases as your income rises. Having a second job can push your total income into a higher tax bracket. 

2. Limited Standard Deduction:

• You can only claim one standard deduction on your tax return, regardless of the number of jobs you hold. If each of your jobs is not taking this into account, your overall taxable income might be higher than anticipated.

3. Incorrect W-4 Form:

• Outdated or inaccurate information on your W-4 forms, especially regarding allowances or multiple jobs, can equal under-withholding. 

4. Other income sources without withholding:

• You have a side job/self-employment you'll need to account for those when determining your tax liability.