This API lets you easily calculate income tax, especially in the context of a spreadsheet.

TLDR: =IMPORTDATA("https://api.taxapi.net/income/status/50000/year")

Everything after /income/ should be replaced with your own variables. status should be either single, married, or hoh (head of household). 50000 would be your MAGI. And year would be the tax year you want to look up. year is optional and if you leave it off, the API will default to the most recent year that it has information about.

For example, if you were single, your MAGI was 50000, and you wanted tax-year 2020, you could do it like this:

=IMPORTDATA("https://api.taxapi.net/income/single/50000/2020")

Check the about page for more information.