I have been using Turbotax for doing my taxes since 2001. I also created a spreadsheet to do the taxes manually and have updated it over the years as my needs have changed. Thought some of you might find it useful. This not only helps me understand the calculation but also allows me to run different scenarios quickly.
It literally takes me 10 min to do my taxes. It is for my situation, married filing jointly but it could easily be adopted for yours. The tabs are pretty self explanatory. I typically updated all IRS info (tax tables, limits etc…) for the next year once I am done with this years taxes. I have attached both 2017 and 2018 tax spreadsheet.
You can use these both to see the impact of the recent tax law changes.
Hope some of you find this useful. I have always matched Turbotax within a 1$. Though, if you find any bugs, please let me know.