Calculate your income in The Netherlands with and without a 30% ruling.

30-income-calculon.pl

# To check if this is up-to-date with the tax rates go to
# http://www.expatax.nl/tax-rates-2015.php and see if there's anything
# newer there.
#
# I make no guarantees that any of this is correct. I calculated this
# at the time and have been updating it when new tax rates come along
# because people keep finding this useful.
#
# There's also an interactive JS version of this created by
# @stevermeister at
# https://github.com/stevermeister/dutch-tax-income-calculator
# although the two seem to show conflicting values and I have no idea
# which one is correct...
use strict;
use warnings;
use Text::TabularDisplay;
use List::Util qw(sum);

my $start = 30_000  || $ARGV[0];
my $end   = 100_000 || $ARGV[1];
my $step  = 1_000   || $ARGV[2];

my @data;
for ( my $salary = $start ; $salary <= $end ; $salary += $step ) {

    push @data => [
        # Your Gross income
        eurofy($salary),

        # Without 30% ruling
        eurofy( $salary - taxes_for($salary) ),

        percentify( taxes_for($salary), $salary ),

        # With 30% ruling
        eurofy( $salary - taxes_for( $salary * .7 ) ),

        percentify( taxes_for( $salary * .7 ), $salary ),
    ];
}

my $table = Text::TabularDisplay->new(
    "Gross income\n(before taxes)",
    "Net income\n(after taxes)",
    "Tax rate",
    "Net income\n(after taxes,\nwith 30% ruling)",
    "Tax rate",
);
$table->add(@$_) for @data;
print $table->render, "\n";
exit;

sub taxes_for {
    my $income       = shift;
    my @tax_brackets = (

        # difference         tax rate
        [ 19_822          => .3650 ],
        [ 57_585 - 19_822 => .42 ],
        [ 0               => .52 ],
    );

    my $money_left = $income;
    my $taxes      = 0;
    foreach my $bracket (@tax_brackets) {
        my ( $progressive_amount, $taxes_for ) = @$bracket;
        my $taxable_amount = $money_left;
        if ( $taxable_amount > $progressive_amount ) {
            $taxable_amount = $progressive_amount if $progressive_amount;
        }
        $money_left -= $taxable_amount;
        $taxes += $taxable_amount * $taxes_for;
        last unless $money_left;
    }
    return $taxes;
}

# From perlfaq5
sub commify {
    local $_ = shift;
    1 while s/^([-+]?\d+)(\d{3})/$1,$2/;
    return $_;
}

sub percentify {
    my ( $amount, $total ) = @_;
    return sprintf "%.1f%%" => ( ( 100 * $amount ) / $total );
}

sub eurofy {
    my ($number) = @_;

    # Round it
    $number = int $number;

    return sprintf( "%s EUR", commify($number) );
}

__DATA__
$ perl 30-income-calculon.pl
+----------------+---------------+----------+------------------+----------+
| Gross income   | Net income    | Tax rate | Net income       | Tax rate |
| (before taxes) | (after taxes) |          | (after taxes,    |          |
|                |               |          | with 30% ruling) |          |
+----------------+---------------+----------+------------------+----------+
| 30,000 EUR     | 18,490 EUR    | 38.4%    | 22,270 EUR       | 25.8%    |
| 31,000 EUR     | 19,070 EUR    | 38.5%    | 22,976 EUR       | 25.9%    |
| 32,000 EUR     | 19,650 EUR    | 38.6%    | 23,682 EUR       | 26.0%    |
| 33,000 EUR     | 20,230 EUR    | 38.7%    | 24,388 EUR       | 26.1%    |
| 34,000 EUR     | 20,810 EUR    | 38.8%    | 25,094 EUR       | 26.2%    |
| 35,000 EUR     | 21,390 EUR    | 38.9%    | 25,800 EUR       | 26.3%    |
| 36,000 EUR     | 21,970 EUR    | 39.0%    | 26,506 EUR       | 26.4%    |
| 37,000 EUR     | 22,550 EUR    | 39.1%    | 27,212 EUR       | 26.5%    |
| 38,000 EUR     | 23,130 EUR    | 39.1%    | 27,918 EUR       | 26.5%    |
| 39,000 EUR     | 23,710 EUR    | 39.2%    | 28,624 EUR       | 26.6%    |
| 40,000 EUR     | 24,290 EUR    | 39.3%    | 29,330 EUR       | 26.7%    |
| 41,000 EUR     | 24,870 EUR    | 39.3%    | 30,036 EUR       | 26.7%    |
| 42,000 EUR     | 25,450 EUR    | 39.4%    | 30,742 EUR       | 26.8%    |
| 43,000 EUR     | 26,030 EUR    | 39.5%    | 31,448 EUR       | 26.9%    |
| 44,000 EUR     | 26,610 EUR    | 39.5%    | 32,154 EUR       | 26.9%    |
| 45,000 EUR     | 27,190 EUR    | 39.6%    | 32,860 EUR       | 27.0%    |
| 46,000 EUR     | 27,770 EUR    | 39.6%    | 33,566 EUR       | 27.0%    |
| 47,000 EUR     | 28,350 EUR    | 39.7%    | 34,272 EUR       | 27.1%    |
| 48,000 EUR     | 28,930 EUR    | 39.7%    | 34,978 EUR       | 27.1%    |
| 49,000 EUR     | 29,510 EUR    | 39.8%    | 35,684 EUR       | 27.2%    |
| 50,000 EUR     | 30,090 EUR    | 39.8%    | 36,390 EUR       | 27.2%    |
| 51,000 EUR     | 30,670 EUR    | 39.9%    | 37,096 EUR       | 27.3%    |
| 52,000 EUR     | 31,250 EUR    | 39.9%    | 37,802 EUR       | 27.3%    |
| 53,000 EUR     | 31,830 EUR    | 39.9%    | 38,508 EUR       | 27.3%    |
| 54,000 EUR     | 32,410 EUR    | 40.0%    | 39,214 EUR       | 27.4%    |
| 55,000 EUR     | 32,990 EUR    | 40.0%    | 39,920 EUR       | 27.4%    |
| 56,000 EUR     | 33,570 EUR    | 40.1%    | 40,626 EUR       | 27.5%    |
| 57,000 EUR     | 34,150 EUR    | 40.1%    | 41,332 EUR       | 27.5%    |
| 58,000 EUR     | 34,688 EUR    | 40.2%    | 42,038 EUR       | 27.5%    |
| 59,000 EUR     | 35,168 EUR    | 40.4%    | 42,744 EUR       | 27.6%    |
| 60,000 EUR     | 35,648 EUR    | 40.6%    | 43,450 EUR       | 27.6%    |
| 61,000 EUR     | 36,128 EUR    | 40.8%    | 44,156 EUR       | 27.6%    |
| 62,000 EUR     | 36,608 EUR    | 41.0%    | 44,862 EUR       | 27.6%    |
| 63,000 EUR     | 37,088 EUR    | 41.1%    | 45,568 EUR       | 27.7%    |
| 64,000 EUR     | 37,568 EUR    | 41.3%    | 46,274 EUR       | 27.7%    |
| 65,000 EUR     | 38,048 EUR    | 41.5%    | 46,980 EUR       | 27.7%    |
| 66,000 EUR     | 38,528 EUR    | 41.6%    | 47,686 EUR       | 27.7%    |
| 67,000 EUR     | 39,008 EUR    | 41.8%    | 48,392 EUR       | 27.8%    |
| 68,000 EUR     | 39,488 EUR    | 41.9%    | 49,098 EUR       | 27.8%    |
| 69,000 EUR     | 39,968 EUR    | 42.1%    | 49,804 EUR       | 27.8%    |
| 70,000 EUR     | 40,448 EUR    | 42.2%    | 50,510 EUR       | 27.8%    |
| 71,000 EUR     | 40,928 EUR    | 42.4%    | 51,216 EUR       | 27.9%    |
| 72,000 EUR     | 41,408 EUR    | 42.5%    | 51,922 EUR       | 27.9%    |
| 73,000 EUR     | 41,888 EUR    | 42.6%    | 52,628 EUR       | 27.9%    |
| 74,000 EUR     | 42,368 EUR    | 42.7%    | 53,334 EUR       | 27.9%    |
| 75,000 EUR     | 42,848 EUR    | 42.9%    | 54,040 EUR       | 27.9%    |
| 76,000 EUR     | 43,328 EUR    | 43.0%    | 54,746 EUR       | 28.0%    |
| 77,000 EUR     | 43,808 EUR    | 43.1%    | 55,452 EUR       | 28.0%    |
| 78,000 EUR     | 44,288 EUR    | 43.2%    | 56,158 EUR       | 28.0%    |
| 79,000 EUR     | 44,768 EUR    | 43.3%    | 56,864 EUR       | 28.0%    |
| 80,000 EUR     | 45,248 EUR    | 43.4%    | 57,570 EUR       | 28.0%    |
| 81,000 EUR     | 45,728 EUR    | 43.5%    | 58,276 EUR       | 28.1%    |
| 82,000 EUR     | 46,208 EUR    | 43.6%    | 58,982 EUR       | 28.1%    |
| 83,000 EUR     | 46,688 EUR    | 43.7%    | 59,636 EUR       | 28.1%    |
| 84,000 EUR     | 47,168 EUR    | 43.8%    | 60,272 EUR       | 28.2%    |
| 85,000 EUR     | 47,648 EUR    | 43.9%    | 60,908 EUR       | 28.3%    |
| 86,000 EUR     | 48,128 EUR    | 44.0%    | 61,544 EUR       | 28.4%    |
| 87,000 EUR     | 48,608 EUR    | 44.1%    | 62,180 EUR       | 28.5%    |
| 88,000 EUR     | 49,088 EUR    | 44.2%    | 62,816 EUR       | 28.6%    |
| 89,000 EUR     | 49,568 EUR    | 44.3%    | 63,452 EUR       | 28.7%    |
| 90,000 EUR     | 50,048 EUR    | 44.4%    | 64,088 EUR       | 28.8%    |
| 91,000 EUR     | 50,528 EUR    | 44.5%    | 64,724 EUR       | 28.9%    |
| 92,000 EUR     | 51,008 EUR    | 44.6%    | 65,360 EUR       | 29.0%    |
| 93,000 EUR     | 51,488 EUR    | 44.6%    | 65,996 EUR       | 29.0%    |
| 94,000 EUR     | 51,968 EUR    | 44.7%    | 66,632 EUR       | 29.1%    |
| 95,000 EUR     | 52,448 EUR    | 44.8%    | 67,268 EUR       | 29.2%    |
| 96,000 EUR     | 52,928 EUR    | 44.9%    | 67,904 EUR       | 29.3%    |
| 97,000 EUR     | 53,408 EUR    | 44.9%    | 68,540 EUR       | 29.3%    |
| 98,000 EUR     | 53,888 EUR    | 45.0%    | 69,176 EUR       | 29.4%    |
| 99,000 EUR     | 54,368 EUR    | 45.1%    | 69,812 EUR       | 29.5%    |
| 100,000 EUR    | 54,848 EUR    | 45.2%    | 70,448 EUR       | 29.6%    |
+----------------+---------------+----------+------------------+----------+