Taxes & Income

Marginal Tax Rate Calculator

Determine your combined marginal tax rate (Federal + State + FICA) to calculate exactly how much tax is owed on overtime, bonuses, or side income.

What this calculator does

The Marginal Tax Rate Calculator estimates your result instantly from the values you enter, using standard taxes & income formulas. Determine your combined marginal tax rate (Federal + State + FICA) to calculate exactly how much tax is owed on overtime, bonuses, or side income. Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate for planning rather than financial advice.

About Marginal Tax Rate Calculator

The Marginal Tax Rate Calculator computes the exact percentage of tax that will be owed on the very next dollar of income you earn from raises, bonuses, consulting gigs, or investment gains.

Formula & Mathematical Calculation

Combined Marginal Rate (%) = Federal Marginal Bracket + State Marginal Bracket + FICA Rate (7.65% or 15.3% SE)

Calculation Example

Single Filer ($95k Salary in California): 22% Federal + 9.3% CA State + 7.65% FICA = Combined Marginal Tax Rate = 38.95% (You keep $0.61 of every extra dollar earned).

Key Benefits

  • Calculates combined marginal rate across Federal, State, and FICA taxes
  • Shows exact net take-home on bonus income, overtime, or secondary side gigs
  • Prevents unexpected tax surprises at year-end
  • Helps evaluate tax deductions (e.g. Traditional IRA saving at marginal rate)
  • Fast and accurate tax analysis tool

How to Use this Calculator

  1. Enter Current Annual Taxable Income
    Input current base earnings.
  2. Select State & Self-Employment Status
    Choose state and W-2 vs. 1099 employment.
  3. Calculate Marginal Rate
    Click Calculate to view marginal tax percentage on additional earnings.

Assumptions & Limitations

What the calculation assumes

  • Every value you enter is treated as an exact, known amount.
  • Rates and contributions are assumed to stay constant for the whole period unless the form asks for them separately.
  • Results use standard financial formulas and ignore fees, penalties and promotional terms that are not entered above.
  • Inflation, tax changes and market volatility are not modelled unless a field for them is provided.
  • Amounts are unit-agnostic: results are returned in the same currency you enter.

What it does not cover

  • Marginal Tax Rate Calculator produces estimates for education and planning, not a quote, offer or professional advice.
  • Real-world outcomes differ when fees, taxes, rounding rules or provider-specific terms apply.
  • Local regulations and tax rules vary by country and change over time; verify current rules for your jurisdiction.
  • Figures are only as accurate as the inputs you supply — check them before acting on the result.
  • For decisions with lasting financial impact, confirm the numbers with a qualified professional.

Frequently Asked Questions

Your marginal tax rate is the percentage of tax applied to your next dollar of income. It is the critical rate for financial decisions, revealing exactly how much you keep from pay raises, freelance income, or bonus compensation.

Your true marginal rate equals: Federal Marginal Rate + State Marginal Rate + Local Tax Rate + FICA (7.65% or 1.45% Medicare). In high-tax states, high earners can face a combined marginal rate exceeding 45% to 50%.

Traditional pre-tax contributions come off the top of your income, saving taxes at your highest marginal rate. A $10,000 traditional 401(k) contribution in a 24% marginal bracket saves $2,400 in federal income taxes.

Marginal rate applies strictly to your highest income tier, whereas your effective rate reflects your average blended tax rate across all income tiers, which is substantially lower.

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Next step: browse the full Taxes & Income calculators or read the related guides for context before you decide.