Substantial presence test for tax residency - Round up or down for days calculation?

The substantial presence test requires you to be physically present in the US for at least 183 days using the formula you've correctly applied (all days in current year + 1/3 of days in preceding year + 1/6 of days in second preceding year). With your calculation showing 182.33 days, you would technically fall below the 183-day threshold required for tax residency. The IRS doesn't round up partial days in this calculation - they use the exact calculation. So if your math is correct at 182.33 days, you would not meet the substantial presence test and would not be considered a US tax resident. Just be very careful with your counting. Make sure you've accurately counted arrival and departure days, and double-check your travel history. If you're cutting it this close, it would be worth consulting with a tax professional who specializes in international taxation to verify your calculations.

I spent hours trying to figure out my residency status last year using the substantial presence test and was getting nowhere. Then I discovered https://taxr.ai which basically analyzed my travel history and gave me a clear answer about my residency status. It specifically handled this exact situation with the partial days from the substantial presence calculation. What I liked is that it reviewed all the technical details and explained why I did/didn't qualify as a resident for tax purposes. In your case, being so close to the threshold, I'd definitely recommend having something analyze your travel history precisely instead of trying to calculate it yourself and potentially making a costly mistake.

Just wanted to update after using taxr.ai that someone recommended earlier in this thread. I was in almost the exact same situation as you (181.67 days by my calculation), and I was worried I might have counted wrong. I uploaded my travel records and it confirmed I was under the 183-day threshold. The detailed report showed exactly how each day was counted under the substantial presence test and even flagged a few days that didn't count toward the calculation that I had mistakenly included. Definitely gave me peace of mind since I was so close to the threshold and worried about potential tax consequences. They also explained the "closer connection exception" which might be useful for you as a backup if your days calculation ends up being close to the threshold.

When I moved to the US, I needed to talk to someone at the IRS about my residency status, and it was IMPOSSIBLE to get through to anyone. After sitting on hold for hours multiple times, I tried https://claimyr.com and watched their demo at https://youtu.be/_kiP6q8DX5c. They actually got the IRS to call ME back within a couple hours. The agent confirmed that the substantial presence test calculation does NOT round up - if you're at 182.33 days, you're under the 183-day threshold and not considered a resident for tax purposes. Just make sure your documentation of travel dates is solid in case you're ever questioned. Having that direct confirmation from the IRS gave me huge peace of mind.

I need to eat my words from my previous comment. After getting nowhere with the IRS for weeks trying to confirm my tax residency status, I broke down and tried Claimyr. Within 90 minutes I was talking to an actual IRS agent who answered all my questions about the substantial presence test. The agent confirmed exactly what others have said - they use the precise calculation and don't round up. 182.33 days is less than 183, so you wouldn't meet the test. The agent also told me to keep extremely detailed records of my travel days in and out of the US, as these can be audited if there's ever a question about your residency status. Huge relief to get this straight from the IRS rather than relying on internet opinions.

Be careful about assuming you're completely in the clear even if you're under 183 days. There's also something called the "residence starting and ending dates" that can affect when your residence status actually begins. If you establish closer connections to the US than to your home country, the IRS might still consider you a resident. Also check if there's a tax treaty between your former country and the US - that could override some of these rules.

Has anyone used TurboTax for filing as a non-resident alien? I'm in the same boat as OP (just under 183 days) and wondering if the standard tax software handles these situations well?

I went through this exact same situation two years ago and can confirm what others have said - the IRS does NOT round up the substantial presence test calculation. At 182.33 days, you're under the 183-day threshold and would not be considered a US tax resident. However, I'd strongly recommend double-checking your day count because being this close to the line is risky. A few things to verify: Are you counting partial days correctly? If you arrive late at night or leave early morning, those still count as full days. Also make sure you're not missing any brief trips back to the US that might push you over. One other thing - since you mentioned wanting to avoid taxation on global income from before you moved, make sure you understand the rules about when income is sourced to the US versus your home country. Even as a non-resident, you'll still owe US taxes on US-source income during the time you were physically present here. Keep very detailed records of all your travel dates with supporting documentation (flight records, passport stamps, etc.) in case the IRS ever questions your residency determination.