For quarterly estimated taxes in 2026, I have untaxed income as a consultant, plus I get a small pension but pay some tax on other income. how do I calculate?

[kimills]

I also get an untaxed pension, but taxes are being taken out of my Social Security and RMDs.

[PatriciaV]

Your best option is to create a new return in the current year version of TurboTax to estimate what your taxes would be. This allows you to make changes to your assumptions until you have the result you want. It's unlikely the tax code will change sufficiently to make this estimate unreliable. But you can update your estimates throughout the year. The IRS does not charge an overpayment penalty. But they also don't pay interest on the excess tax when you file next year with a refund due.

We recommend TurboTax for Desktop for this purpose because you can view all forms and not just Form 1040. Also, you can prepare as many returns as you like in the desktop version, including any states that you already purchased, for free as long as you don't actually file the return. Note that you won't be able to use this test return to file next year because TurboTax software is specific for the tax year of filing.

To create a new return in TurboTax Online, you'll need to set up a new account using a different email address.

[baldietax]

Agree with comment to use Turbotax or some other online calculator to estimate your 2026, this one may be helpful

https://www.dinkytown.net/java/1040-tax-calculator.html

but also consult Form 2210 and Form 1040-ES for other guidance on safe harbor.  You need to pay thru withholding or timely estimated taxes, the smaller of 100% of your 2025 tax (see Form 2210 for definition, and apply 110% if your 2025 AGI was > 150k or 75k if filing MFS), or 90% of your 2026 tax.  To the extent you can increase withholding that decreases the ES due, and withholding is always assumed to be timely even if increased later in the year.

If your consulting income is variable or your income increases overall then you may be better off using the 100/110% of 2025 tax method as that is a known amount assuming withholding is known you can simply pay fixed quarterly ES payments, the only disadvantage is it can sometimes be an overpayment if 90% of 2026 tax is lower obviously.  If you use 2026 tax then you have to make a good estimate and track it during the year.

The deadline for Q1 ES was 4/15, if you determine that was due you should pay that ASAP to stop the penalty for Q1 from accruing daily.

Finally if your income is variable and you have one-off events later in the year and did not set up ES payments evenly over the year then you may have a penalty but may be able to reduce or eliminate it by using the Annualized Income method on Form 2210 - but that is extra filing work as you have to self-calculate a quarterly AGI, withholding etc so it's generally better to plan ahead and try to avoid that filing method.

Hope that helps - check instructions for Forms 2210 and 1040-ES also.