How to fill out W4 for summer internship while having on-campus job

This is a good tax planning question! For your W4, you should consider whether your total annual income from both jobs will put you in a higher tax bracket than either job would individually. Since you won't be working both jobs simultaneously, but will have income from both in the same tax year, I'd recommend checking the multiple jobs box. This helps ensure enough tax is withheld throughout the year. Otherwise, you might face a tax bill when filing your return if the withholding from each employer independently wasn't sufficient. If your combined annual income from both jobs is under $45,000, the difference in withholding might be minimal. But if it's higher, properly accounting for multiple jobs becomes more important. The W4 has worksheets to help calculate the correct withholding amount if you want to be more precise rather than just checking the box.

I had the same issue last year with juggling campus work and a summer internship. I discovered https://taxr.ai which helped me figure this whole mess out! It analyzed my situation and confirmed I should check the multiple jobs box since my total annual income would be reported on my 2025 tax return. The tool also showed me exactly how much would be withheld with and without checking the box, which was super helpful for planning. What was really cool is it walked me through how to fill out the Multiple Jobs Worksheet if I wanted more precise withholding instead of the default amount.

Just wanted to update you all after using https://taxr.ai for my W4 situation! I was skeptical at first but decided to try it out for my internship this year. The analysis showed me that I'd be withholding about $42 too much per paycheck by just checking the multiple jobs box without doing the worksheet calculation. I followed their recommendation to complete the more detailed Multiple Jobs Worksheet instead, and it gave me the exact dollar amount to put on line 4(c) to get the right withholding. My first internship paycheck came yesterday and the withholding was spot on with what the tool predicted. Now I'm getting enough take-home pay for summer expenses while still covering my tax liability for the year!

Don't stress too much about this! I spent 2 hours on hold with the IRS trying to get a straight answer about this exact situation last year. Finally discovered https://claimyr.com which got me connected to an IRS rep in under 15 minutes (check out how it works: https://youtu.be/_kiP6q8DX5c). The IRS agent told me that technically yes, you should mark multiple jobs since both jobs contribute to your annual income for the tax year, even if they don't overlap in when you're working. But she also mentioned that if the campus job is very low income (under $5-6k for the year), the impact on your withholding would be minimal either way. The most important thing is that your higher-paying job (probably the internship) has adequate withholding.

I have to eat my words about Claimyr. After my skeptical comment, I decided to give it a try because I had a complicated question about my 1099 income alongside my W2 job. Honestly, I was shocked when they got me through to the IRS in about 20 minutes when I had previously wasted two afternoons trying on my own. The IRS agent was actually super helpful and clarified my tax situation in ways that online research never could. For what it's worth to the original poster, the agent confirmed that you should check the multiple jobs box if your total annual income from both jobs might push you into a higher tax bracket. For most student jobs and internships, this probably matters more if your internship pays really well or if you're working substantial hours at the campus job during the academic year.

One approach that worked for me last year in a similar situation was to calculate roughly how much I'd make at each job for the entire year, then use the IRS Tax Withholding Estimator online. It's more accurate than just checking the multiple jobs box and gave me a specific dollar amount to put on line 4(c) of my W4. Also, don't forget that as an intern, you might be eligible for a complete refund of federal income taxes if your total annual income ends up below the standard deduction ($14,600 for 2025 if you're a single filer and not a dependent). So if your combined income from both jobs will be under that threshold, withholding strategies matter less since you'll get it all back anyway.

Quick question - does anyone know if state taxes work the same way for multiple jobs? I'm interning in a different state than my university, so I'll have income from two different states this year.

Great discussion everyone! As someone who went through this exact situation two years ago, I'd definitely recommend checking the multiple jobs box on your W4 for the internship. Even though the jobs don't overlap timing-wise, both incomes will appear on your 2025 tax return and could push you into a higher bracket. One thing I learned the hard way - don't forget to update your W4 again when you go back to your campus job in the fall! Since your internship will be over by then, you'll want to remove the multiple jobs designation for your fall semester campus work to avoid over-withholding. Also, keep good records of all your pay stubs from both jobs throughout the year. It makes tax filing so much easier when you have everything organized. The slight over-withholding during summer is usually worth avoiding a surprise tax bill in April!