The IRS in a news release announced the release of a new online tax withholding estimator, replacing the previous withholding calculator. The new calculator, found at https://apps.irs.gov/app/tax-withholding-estimator, is designed to be both simpler to use and mobile friendly (that is, easier to use on smart phones).
The news release describes the improvements to the calculator as follows:
The IRS took the feedback and concerns of taxpayers and tax professionals to develop the Tax Withholding Estimator, which offers a variety of new user-friendly features including:
Plain language throughout the tool to improve comprehension.
The ability to more effectively target at the time of filing either a tax due amount close to zero or a refund amount.
A new progress tracker to help users see how much more information they need to input.
The ability to move back and forth through the steps, correct previous entries and skip questions that don’t apply.
Enhanced tips and links to help the user quickly determine if they qualify for various tax credits and deductions.
Self-employment tax for a user who has self-employment income in addition to wages or pensions.
Automatic calculation of the taxable portion of any Social Security benefits.
A mobile-friendly design.
In addition, the new Tax Withholding Estimator makes it easier to enter wages and withholding for each job held by the taxpayer and their spouse, as well as separately entering pensions and other sources of income. At the end of the process, the tool makes specific withholding recommendations for each job and each spouse and clearly explains what the taxpayer should do next.
The IRS also offers an infographic outlining the steps a taxpayer is take to use the online tool.
 IR-2019-139, August 6, 2019, retrieved August 8, 2019
 https://www.irs.gov/pub/irs-utl/tax-withholding-estimator-infographic.pdf, August 6, 2019, retrieved August 8, 2019