If I use my 2018 tax file to estimate 2019 income, how can I make sure I still have my original 2018 tax file when I exit Turbo Tax?

[HelenaC · Accepted solution]

If you are using TurboTax CD\Download, do File, Save as, and rename it something like 2019 estimate.

If you are using TurboTax Online, don't enter amounts over your 2018 income tax return. See instead Can TurboTax calculate next year's federal estimated taxes?