Can Taxcaster is estimate 2018 taxes? When will Taxcaster be updated with 2018 tax tables? I don't see an option to choose 2017 or 2018 tax year.

[Opus 17]

I don't about the web site, but the TaxCaster smartphone app (android or iOS) includes 2018.  The default method looks at your 2017 income and deductions using the 2017 rules, but then there is a tab to review 2018, which gives a summary, and a details button gives you the details.  This would also work by using your expected 2018 numbers, ignore the 2017 result, and go straight to 2018.