Can Turbotax help with accurately calculating the amout I can covert from traditional to Roth IRA before end of 2025 to stay under a tax bracket

[fanfare]

Come back in mid-December after the 2025 TurboTax is available and you can estimate your 2025 AGI before conversion.

You are still in the bracket if your AGI after Conversion is less than the top value of AGI for that bracket.

For the new 2025 bracket ranges, see GOOGLE.

Leave enough business days for the IRA custodian to process your request by Dec 31.

@Harish1 

[dmertz]

With regard to determining your marginal tax rate, fanfare's post should generally be referring to checking the amount of income taxable as ordinary income rather than AGI.  That could be the amount on Form 1040 line line 15, but there are also several other ways that the amount of income taxable as ordinary income is determined, such as on Schedule D Tax Worksheet or the Qualified Dividends and Capital Gain Tax Worksheet.  AGI does matter if you are subject to Medicare IRMAA and need to consider the IRMAA thresholds, if you are approaching the $200,000 AGI threshold where Net Investment Income Tax kicks in, or if you receive any tax credits that depend on AGI.

[Harish1]

Thank you. 

[dmertz]

For preparing a test tax return you'll want the download version of TurboTax which typically comes out in early November.  However, the initial releases of TurboTax usually do not have all of the updates needed for the tax year, so you'll likely need to use a few overrides in forms mode until TurboTax has been updated sufficiently.  You can also get a rough idea by preparing a test tax return using the previous year's version TurboTax  with overrides, but that can take quite a few overrides.