Before the TCJA was passed, the IRS adjusted the rates and brackets for inflation using the Consumer Price Index (CPI). Once the act was passed, the IRS began using the Chained Consumer Price Index (C-CPI) to adjust.
There are still seven separate income tax brackets. In 2018, most of the rates were lowered for each income bracket, meaning many of your clients paid less income tax.
In 2019, the rates stayed the same, but now include a different equation to calculate your clients’ income tax. The brackets also expanded. This chart is included below for your reference, and TaxSlayer Pro takes care of all the math for you.