Personal Income Tax in Japan 2012

# http://www.worldwide-tax.com/japan/japan_tax.asp
# http://www.hi-ho.ne.jp/yokoyama-a/taxationinjapan.htm
# http://www.japan-guide.com/e/e2206.html
# 2DO: requires verification of calculation rules

JapanTax <- function(income) {

  if (income<1.95e6)                     pit <- 0.05*income

  if (income>1.95e6 && income<=3.30e6)   pit <- 0.10*income

  if (income>3.30e6 && income<=6.95e6)   pit <- 0.10*3.3e6+0.20*(income-3.30e6)

  if (income>6.95e6 && income<=9.00e6)   pit <- 0.10*3.3e6+0.20*(9.00e6-3.30e6)+0.23*(income-9.00e6)

  if (income>9.00e6 && income<=18.00e6)  pit <- 0.10*3.3e6+0.20*(9.00e6-3.30e6)+0.23*(18.00e6-9.00e6)+0.33*(income-9.00e6)

  income.postPIT  <- income-pit

  municipal       <- income.postPIT*0.06
  prefectural     <- income.postPIT*0.04

  income.net      <- income.postPIT-municipal-prefectural

  taxes           <- pit+municipal+prefectural

  list( income.net=income.net, taxes=taxes, tax.rate=taxes/income )

}

# example:
JapanTax(5e6)

# result
> JapanTax(5e6)
$income.net
[1] 3897000

$taxes
[1] 1103000

$tax.rate
[1] 0.2206