How can I get my estimated 2018 taxes to file quarterly (self-employed) if I've already filed my 2017 taxes?

[aandrew-smith]

This is the first year I will be self-employed.

[BMcCalpin]

You don't need TurboTax to make your estimated vouchers - you can do them yourself.

First, you need to do a mock run of what your taxes might be in 2018 (yes, this will involve guessing). Then you can divide the total by 4 and pay one quarter each quarter.

Or, if this involves too much guesswork and you want a safe number, take 100% of your 2017 tax due (generally line 44 on the 1040 - "Tax") and divide by 4. Pay one fourth of that number each quarter.

In this case, you will be assured to avoid the underpayment of tax penalty, because one of the exceptions is paying 100% of the previous year's tax (which, of course, may or may not be enough for 2018 with your very different circumstances).

You can find the 1040ES vouchers at the IRS website - https://www.irs.gov/pub/irs-pdf/f1040es.pdf