Which federal bracket this lands in
The $16,100 standard deduction leaves $23,420 of taxable income, which puts the last dollar in the 12% federal bracket. Only $11,020 of it is actually taxed at 12% — the income below $12,400 is taxed at the lower rates first, which is why the effective rate lands well under the bracket number. The 12% band runs to $50,400, so a raise of about $26,980 would be needed before any dollar is taxed at 22%.
Where this sits in Montana's schedule
Montana runs a graduated schedule of 2 bands. After $16,100 of state deductions it taxes $23,420, putting the top dollar in the 4.7% band and producing $1,101 of state tax — 2.79% of gross pay. Its 4.7% band ends at $47,500 of state taxable income, $24,080 above where this salary lands.
Marginal rate is not the rate paid
Federal income tax of $2,562 on $39,520 of gross pay is 6.48% of the salary, against a 12% marginal bracket — a gap of about 5.5 points. The bracket describes the next dollar earned, not the pay already earned, and quoting the bracket as the tax rate overstates the bill by $2,180 at this salary.
What a $1/hr raise is actually worth
A dollar more an hour is $2,080 more a year at 2,080 paid hours. Against a combined marginal rate of about 24.35% -- the 12% federal band, Montana's 4.7%, 1.45% Medicare and 6.2% Social Security -- roughly $1,574 of that reaches the bank, or about $0.76 of the extra dollar.