IRS 2025 Tax Withholding Calculator Question

Hi All!

Im new to this subreddit but I've been using the IRS Tax Withholding Calculator since I just got married in Feb 2025. I was going to change my W4 form to married filing joint, my spouse currently lives in Canada but has not worked or plans to work this year. The IRS calculator says my projected refund is $7340 which is abnormally high, my previous tax returns have been around $2,000-$3,000 but i'm assuming its because my wife does not have a job and i'll be getting the tax benefits of MFJ. I also do not have any additional deductions or credits that I would apply for this current tax year.

What i'm confused about is when I put in the same information into Turbotax or HR Block, both say my refund for the year will be around $600. Why is there such a big discrepancy between those 2 calculators vs the IRS calculator? The IRS calculator told me to enter $5985 in step 3. Below is more information if that can help anyone answer my question! All these calculations are based off of me using the standard deduction.

Paid Biweekly: $4463 Gross
YTD $39,777
Anticipate making around $102,196 since i'll be going on vacation in august
Current Federal Withholding Biweekly: $574.48
Federal Withholding YTD: $6340.82

Sidenote: My wife also has no assets to claim such as real estate, stocks, etc.