Estimated Quarterly Payments

[JotikaT2]

It sounds like you want to know how the estimated quarterly payments are calculated.  If so, please see this link for more details.

If you are trying to understand more about when you might need them, this link breaks the details out more to assist.  Essentially, estimated quarterly payments are needed if you have a business or earn income from other sources where income taxes are not withheld, but which are high enough to generate a tax liability.  The estimated tax payments are intended to pay for the taxes due as the income is earned.