Federal Income tax:
28% is marginal tax rate, not average tax rate.
for instance,
for 2003
$45,000 - $3,050( exemption for one person) - $4,750(single filing) = $37,200
$37,200
for income $0-$7000 tax rate 10%
for income $7000-$28400 tax rate 15%
for income $28400 - $68800, tax rate 25%
In your case:
tax liability:
7000 * 10% = 700 +
(28400 - 7000) * 15% = $3210 +
(37200 - 28400) * 25% = #2200
Federal tax $6100
the average federal income tax rate for you is 13.5% (6100/ 45000)