Get your taxes done using TurboTax

Thank you. I'm trying to "tweak" the estimated taxes that I have to pay quarterly. I know my withholding from social security and my IRA, however, to determine the amount of estimated taxes, the only number I'm missing is the withholding from my pension. Turbotax asks me for withholding from other sources. 

 

Even though estimated taxes are just estimates, I should be able to calculate the withholding for single and married file jointly. It's a. monthly payment. Isn't there a simple calculation where I input the monthly amount and it tells me the withholding for single and married?