Bug in 2026 Estimated Tax Payments (too low)?

[user17714745664]

The quarterly estimated tax payments for 2026 look too low.  I selected the option to pay 100% of my actual 2025 taxes ($23,282), round up to nearest $10, and no 2025 refund applied. TurboTax calculates quarterly payments of $5170, which totals $20,680.  This is $2602 less than my 2025 taxes.  I can't figure out if there is another setting that would explain the apparent discrepancy.

I use the desktop Home & Business version.  I ran the updater this morning which installed updates, then rebooted my PC. Get same result after the update.

[user17714745664]

I just figured out where the discrepancy is coming from by looking at the underlying Worksheets. TurboTax is assuming the same withholding that happened in 2025 will apply to 2026. So... It takes total 2025 tax, subtracts the assumed withholding ($2623), then divides the result by 4 and rounds up to nearest $10. It would be nice if TurboTax would expose this assumption in the step-by-step so the results make sense.  User shouldn't have to dig this much to puzzle out what looks like a discrepancy. Also... user may have different withholding this year so TurboTax should confirm before applying the assumption of same withholding as 2025.

[HK-NYC]

There appears to be multiple bugs in the TurboTax (TT) code in relation to the estimated taxes payable for 2026. 

As you have discovered, it assumes that the same withholding in 2025 will be applied in 2026.  In my case, it was worse as my W-2 income fell to zero (retired in 2025) and the bug resulted in TT informing me that I have no Estimated Federal Tax to pay in 2026 although I expect to continue to have other sources of income which would be taxable. 

I had to go into the worksheet to ENTER $0 as the withholding for 2026 - the field being blank was not enough even though TT conventionally treats other empty value field to be $0.  That helped and the app generated an estimated tax number and the 4 estimated tax forms. 

HOWEVER, the estimated tax for 2026 was still too low to be believed - it came up to be less than the estimated State and City taxes - an impossibility as the Federal tax rates are higher on the same incomes and certain incomes such as SSI are not taxed at the State level. 

On further analysis, it appears that TT did not accurately bring in the appropriate value into the line "Total of your other taxable income and losses" in the "Other Income" section of their Estimated Tax and Form W-4 Worksheet.  From what I could deduce (based on the number TT used for the 2025 column), it brought in my self-employment income INSTEAD OF the total of my taxable interests, ordinary dividends and the taxable portion of my social security income.

I have yet to go back into the app or worksheet to figure out how to resolve for the understated "other income".   Not sure if TT will allow me to over-ride any of the mis-stated number.   I'll report later should I have figured out this bug.  

As underpayment of Estimated Taxes WILL result in a penalty, TT should fix this ASAP or be responsible for this flaw in their coding.

p.s. I'm using the TT Deluxe desktop version

[user17728328836]

Same for me using the desktop Premier version of Turbotax.  Seems very different from past years and I don't appreciate the last 2-3 years changing the look of the "fast" question overlay.  I know people more savvy than I am, to just enter directly on the forms.  Every year of late, a new crop of young programmers changing things that aren't broken.

[HK-NYC]

I've figured out that the under-estimation of Estimated Tax for 2026 was due to the fact that "Other Income" lumps together the following:

- Interest income

- Dividend income

- Retirement income

- Taxable Social Security benefits

- Income from S corporations, estates and trusts, and partnerships (but not partnership self-employment income)

- Rental properties (or your allowable losses from rentals)

- Any other miscellaneous taxable income or loss you expect to have next year

TurboTax should have separated them out.  You have to click on the Learn More link to figure that out and then add up those incomes yourself and enter that total into that one box.  For retirees, these categories form the bulk of their income.  TT's aim must be to make it easier and more secure for the user to get their Estimated Tax number. 

[WendellL]

I'm finding that when I enter anticipated income from 1099-Rs in "other income," TT takes no account of it at all in calculating estimated taxes for next year.  Since I don't anticipate significant income changes next year, I can just divide this year's taxes into four quarterly payments manually. . . but it would be nice if the software were accurate. Any suggestions for fixes?

[soho333]

The Federal estimated taxes section is definitely buggy.  Along with many of the other posts in this thread, there appears to be 2 additional issues:

1. ES & W4 Worksheets - All the inputs I have provided seems to have been captured correctly. That said, under the section on page 2, "Enter the Tax Payments You've Already Made for Your 2026 Tax Return", if you enter inputs for federal income tax actually withheld from your paycheck to date, TT will calculate the taxes paid to date and derive a "Balance of payments needed or (expected refund)".  So far so good.

The issue I see is that if you enter values for federal taxes already paid in 2026, this amount is not carried through to the "Estimated Tax Options" form, "Expected withholding for 2026" field to reduce your remaining estimated tax payments so you potentially will pay more.  I corrected for this by doing a manual override of the form (note, you need to go to the TurboTax top level menu > Edit > Override) and changing the field, "Expected withholding for 2026" to have the federal tax withheld paid to date.  At that point, my 1040ES was generated correctly with what was remaining for the year.  Not everyone will have this situation, but wanted to share this just in case.

TT Mac version: Home and Business edition.