If you are using the Online version, do NOT change anything on your return. You would have to start with a new account and do a test return. You don't have to pay unless you want to print it out.
Or Here's the link for the current TaxCaster tool:
https://turbotax.intuit.com/tax-tools/calculators/taxcaster/ How to start another return in the Online version
https://ttlc.intuit.com/questions/1894512-how-do-i-start-a-second-return-in-turbotax-online There is one thing you can do in your current return. You can go though the Estimated Tax section which will prepare estimated payments for next year. That may help you calculate what you might owe. You can just type W4 in the search box at the top of your return , click on Find. Then Click on Jump To and it will take you to the estimated tax payments section. Say no to changing your W-4 and the next screen will start the estimated taxes section.
OR go to
Federal Taxes or Personal (H&B version)
Other Tax Situations
Other Tax Forms
Form W-4 and Estimated Taxes - Click the Start or Update button
To get back into your return, try this, you can sign back onto your account, and click on Add a State. This should get you back into your return.
The Desktop installed program could be used. It can do unlimited returns and has a What-If worksheet. You can also save and copy a return with another name to test in.
