2026 Est Tax Computation

Forum|Forum|6 months ago
March 15, 2026
4 replies
106 views

Is there a way to see how TurboTax derives its numbers? Specifically, on the 1040ES workshheet I do not understand how the computation for 2026 projected itemized deductions is derived. I double clicked on the computed amount but apparenty drilling down to the coputation is not possible.

Forms

ReneV4

Level 8

Yes. In TurboTax Desktop, you can review several Worksheets to help you see how the estimated numbers are derived.

In Forms Mode, click on Open Form and type "What-if" in the search box. Select the "What-If Worksheet" to open. This Worksheet will show you the side-by-side comparison of your actual 2025 numbers and your 2026 projections. To populate the numbers in Column 2, select the "Copy column 1 to column 2" box at the top left of the Worksheet.

You can also view the "Estimated Tax Payment Options", by clicking Open Form and typing those words into the search box. Ensure you highlight "Estimated Tax Payment Options" when it appears, and not the Vouchers themselves, which will be located just below.

If the 1040-ES projection is causing your estimated vouchers to be too high or too low, don't try to fix the 1040-ES worksheet directly. Note about Forms Mode. If you see a number in red, that indicates an override. While you can override directly on the Worksheet, it is always better to use the Step-by-Step method so that the software can calculate the other dependencies correctly.

Go to Other Tax Situations located to the right of the Deductions & Credits tab
Scroll down to Other Tax Forms
Select Form W-4 and Estimated Taxes
Choose Estimates on the Adjust How Much Tax You Pay screen, then Continue
This allows you to manually enter expected amounts for 2026 rather than letting the software "guess" based on 2025

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mnfriedman1Author

Level 4

Thank you for your reply, but my question may not have been sufficiently clear.

I have bee able to get to the "ES & W4 Wks" worksheets using the left column of the Forms mode. My question pertains to how a number on the worksheet was computed. Speciically, how the amount of itemized deductions used in the "Deduction Allowed" line was derived.

I am aware that I can override the amount appearing on the 1040ES vouchers, but then I need to compute the tax myself.

Thanks again.

JohnB5677

Level 15

You wanted to know "how the amount of itemized deductions used in the "Deduction Allowed" line was derived."

It uses the current year amounts with adjustments for the upcoming year's tax limits.
The deductions are listed on your 1040 Tax return on lines 11-24. All of the itemized deductions as listed on line 12e of your return are shown on Schedule A.

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