The worksheet and tables are in the instructions for schedule A. Note that this is the 2017 instructions, 2018 is not released yet. There will probably be a small inflation adjustment in the figures.
<a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/i1040sca.pdf">https://www.irs.gov/pub/irs-pdf/i1040sca.pdf</a>
