Marginal Tax Rate Calculator Formula

Understand the math behind the marginal tax rate calculator. Each variable explained with a worked example.

Formulas Used

Marginal Rate

marginal_bracket = marginal_rate

Tax on Extra Income

tax_on_raise = raise_amount * marginal_rate / 100

After-Tax Extra Income

after_tax_raise = raise_amount * (1 - marginal_rate / 100)

Variables

VariableDescriptionDefault
taxable_incomeTaxable Income(USD)75000
raise_amountRaise or Extra Income(USD)5000
marginal_rateDerived value= taxable_income <= 11600 ? 10 : (taxable_income <= 47150 ? 12 : (taxable_income <= 100525 ? 22 : 24))calculated

How It Works

Marginal Tax Rate

Your marginal rate is the tax rate on your next dollar of income. A $5,000 raise at 22% marginal rate means $1,100 in additional tax.

After-Tax Raise = Raise x (1 - Marginal Rate)

Important: Getting a raise never results in less take-home pay. Only the additional income is taxed at the higher rate.

Worked Example

$75,000 income with a $5,000 raise.

taxable_income = 75000raise_amount = 5000
  1. 01Marginal rate at $75,000 = 22%
  2. 02Tax on $5,000 raise = $5,000 x 22% = $1,100
  3. 03After-tax raise = $5,000 - $1,100 = $3,900

Ready to run the numbers?

Open Marginal Tax Rate Calculator