After completing your tax return and filing your taxes, you should have a good idea of whether you are withholding enough from your paycheck. Micheal Devine from the IRS says a periodic check of your withholding is a good idea.
Devine says the Withholding Estimator from the IRS Webpage is very easy to use.
It can also help when there have been changes in your status or your family status.
The Withholding Estimator is one of the tools found at IRS.gov.