Every year, the executive branch reports to Congress the titles and salaries of everyone working in the White House. In the first four years of the Trump administration, the annual cost of all White House office staff has averaged $38 million. That is below the average during the last four years of the Obama administration, $38.9 million.
In Trump's first year in office, he spent $4 million less than his predecessor spent the previous year, perhaps reflecting the pace of filling positions in a new Presidency. Overall head count is up by about 40 people since then, to 403 in the 2020 report.