It appears that you are filling out the 2018 Estimated Tax Worksheet on page 8 of Form 1040-ES for 2014. Line 12b of the worksheet is basically your 2017 tax, with some possible adjustments. The instructions for line 12b tell you how to calculate the amount to enter. The instructions are on page 6, starting at the bottom of the left column and continuing to the right column.
You might find it easier to use TurboTax to figure your estimated tax for 2018. The FAQ at the following link tells you how to calculate your 2018 estimated tax in TurboTax.
https://ttlc.intuit.com/questions/2584228-can-turbotax-calculate-next-year-s-federal-estimated-taxes