quick function to estimate income tax for 2022

est-income-tax.R

est_income_tax <- function(x, jointly = F) {
  # SOURCE
  # https://www.irs.gov/newsroom/irs-provides-tax-inflation-adjustments-for-tax-year-2022
  brackets <- c(0,10275,41775,89075,170050,215950,539900)
  if(jointly) {
    # brackets are double for jointly except for the last one
    brackets <- 2 * brackets
    brackets[length(brackets)] <- 647850
  }
  
  rate <- c(.10,.12,.22,.24,.32,.35,.37)
  taxable <- (x - brackets)
  taxable[taxable < 0] = 0 # not taxed if < 0
  d_taxable = abs(diff(taxable))
  
  if(x > max(brackets)) {
    d_taxable = c(d_taxable, tail(taxable,1))
  } else {
    d_taxable = c(d_taxable, 0)
  }
  
  sum(d_taxable * rate) # marginal tax rate
}