Calculate and Pay Estimated Tax for Current Tax Year

[cririuss_ca]

I was unemployed in 2025 and living on my savings, with some income from CD interests  and stock dividends .  I also did a Roth Conversion around October 2025.  I didn’t pay estimated tax (no concept of this until TurboTax 2025 assessed an underpayment penalty on Form 1040).  

For this year  I want to avoid the penalty tax by start  paying estimated taxes on time for Tax Year 2026 - my tax situation may be the same (will make  another Roth IRA Conversion)  and I have a few questions:

a.  Calculate and  pay the quarterly Federal estimated tax amount by dividing the 2025 Tax amount computed by Turbo Tax (minus the penalty of course) from Form 1040  by 4 and make the payment each quarter (starting with April 15, then June 15, Sep 15, and Jan 15 of next year)?    I assume I do the same formula for my CA state tax. 

b. I do have an IRS account where I view and download  tax transcripts each year.  I understand  I can pay estimated taxes directly to IRS (federal) - do I need to send a 1040-ES?  And I assume IRS will issue a receipt of a payment online or via email? 

c. Same question but for CA state tax (still haven't created an account in CA FTB)

[Bsch4477]

Agree with all you posted. The IRS will email you a confirmation if you request it but it gives you a confirmation on the site. 

[Mike9241]

if you use the IRS website to pay, you do not send the IRS the 1040-ES forms. also print or save as a pdf the receipt that will be offered.

california is a bit wacky when it comes to estimated tax payments. same dates but 30%, 40% 0% 30%

see this webpage

https://www.ftb.ca.gov/forms/2026/2026-540-es-instructions.html