The Tax MathNotebook

Volume I

No. 27, Apr 2026

Filed under: federal income tax, progressive brackets, FICA, deductions.

§ Front Matter

The Effective Tax Rate, Carefully Worked Out in Long Hand

Most people quote their tax bracket as if it were their tax rate. It is not. The bracket is the rate on the last dollar; the effective rate is the rate on the average dollar, and the gap between them is where progressive taxation does its quiet redistribution work. This notebook shows the arithmetic, line by line, so the next time someone tells you a raise will cost them money you can hand them the page that proves otherwise.

Skip to the calculatorRead § II first

The effective tax rate is total tax paid divided by total income. That is the whole definition. Everything else is bookkeeping. What makes it interesting is that the answer is almost always substantially smaller than the bracket label most people memorize. A single filer earning seventy-five thousand dollars sits inside the twenty-two percent bracket, but pays an effective federal income tax rate near ten percent. The first sixteen thousand one hundred dollars are sheltered by the standard deduction. The next twelve thousand four hundred are taxed at ten. The next thirty-eight thousand at twelve. Only the very last eight thousand five hundred hit the twenty-two percent rate at all.

Definition 1.1

Effective rate  = total tax paid ÷ total gross income

example. (1,240.00 + 4,560.00 + 1,870.00) ÷ 75,000  =  7,670 ÷ 75,000  =  10.2%

Worksheet, Tool 1

Try your numbers

$
$20,000$1,000,000

Standard deduction: $16,100

$
$0$24,500 limit

Effective rate

10.2%

federal income tax / gross

Marginal rate

22.0%

rate on the next dollar

FICA rate

7.6%

Soc. Sec. + Medicare

Combined

17.9%

federal income + FICA

Schedule A, Bracket-by-Bracket Arithmetic

BracketRange of taxable incomeIncome in bracketTax
0%standard deduction$16,100$0
10%$16,100 – $28,500$12,400$1,240
12%$28,500 – $66,500$38,000$4,560
22%$66,500 – $75,000$8,500$1,870
Federal income tax (sum)$7,670

The Identity

Effective rate  = $7,670 ÷ $75,000

= 10.2%

The Gap

Your bracket is 22.0%, but you do not pay 22.0% on every dollar. The gap of 11.8% is what progressive brackets buy you.

Filing

Single

Taxable income

$58,900

Social Security

$4,650

Medicare

$1,088

GrossEffective fed.MarginalFICACombined
$25,0003.6%12%7.65%11.2%
$50,0007.6%12%7.65%15.3%
$75,00010.2%22%7.65%17.9%
$100,00013.2%22%7.65%20.8%
$150,00016.5%24%7.65%24.1%
$200,00018.4%24%7.2%25.5%
$300,00022.7%35%5.6%28.3%
$500,00027.6%35%4.3%31.9%
$1,000,00032.0%37%3.3%35.3%

Standard deduction applied. FICA = Social Security 6.2% (capped at $184,500) + Medicare 1.45% + Additional Medicare 0.9% above $200,000 (single).

2026 Single Filer

  • 10%$0 to $12,400
  • 12%$12,401 to $50,400
  • 22%$50,401 to $105,700
  • 24%$105,701 to $201,775
  • 32%$201,776 to $256,225
  • 35%$256,226 to $640,600
  • 37%$640,601 and up

Standard deduction 2026: $16,100.

Worked example, single, $75K

  1. Gross 75,000 − std. ded. 16,100  =  58,900 taxable.
  2. 12,400 × 0.10  =  1,240.00
  3. 38,000 × 0.12  =  4,560.00
  4. 8,500 × 0.22  =  1,870.00
  5. Sum  =  7,670.00 federal tax.
  6. 7,670 ÷ 75,000  =  10.2% effective.

The 22% bracket label is correct, but only $8,500 of the $75,000 is taxed at 22%.

The federal income tax effective rate sits below FICA for most workers earning under fifty thousand dollars. Social Security takes 6.2 percent of every wage dollar up to the 2026 wage base of $184,500, and Medicare takes 1.45 percent of every wage dollar with no cap and an additional 0.9 percent above two hundred thousand. For a $50,000 single earner, FICA totals $3,825, almost exactly the $3,820 federal income tax bill on the same paycheck. FICA is also nearly impossible to reduce, while federal income tax bends to dozens of deductions and credits.

State income tax adds zero to ten percentage points more, depending on the state. A $75,000 earner in Texas pays approximately 17.9 percent combined federal effective rate (income tax + FICA). The same earner in California pays closer to 22 percent once the state's roughly 4.2 percent effective state rate is layered on top. The geographic spread is large enough to swamp most personal-finance differences between two otherwise identical earners.

One quirk worth noting: FICA is regressive on the way up. A $500,000 earner pays the same $11,439 in Social Security as a $184,500 earner, a Social Security rate of just 2.3 percent rather than 6.2. Add the Medicare surtax and total FICA for a $500,000 earner runs near 4.3 percent of gross. The combined federal effective rate at high incomes is therefore dominated by federal income tax, not FICA, the opposite of the picture at low incomes.

Q.1What is an effective tax rate?›
Your effective tax rate is the actual percentage of your total gross income that goes to federal income tax. Total tax divided by total income. A single filer earning $75,000 in 2026 pays roughly $7,700 in federal income tax after the standard deduction, an effective rate of about 10 percent. The 22 percent label some people quote is the marginal rate on the last dollar, not the rate on every dollar.
Q.2Why is my effective rate lower than my tax bracket?›
Because the United States taxes income progressively. Your bracket only describes the top slice of your income. After the standard deduction shelters the first $16,100 (single, 2026), the next $12,400 is taxed at 10 percent, the next $38,000 at 12 percent, and only the income above that runs at 22 percent. The effective rate averages all of these together and always lands below the top bracket.
Q.3Can a raise put all my income into a higher bracket?›
No. This is the most expensive misconception in personal finance. Brackets are slices, not cliffs. A $10,000 raise that crosses into the 24 percent bracket is taxed at 24 percent only on the portion that crosses. Your earlier income keeps its lower rates. You always take home more after a raise. The only edge cases involve credit phase-outs, and even those rarely produce a real take-home reduction.
Q.4Does FICA count as part of my effective rate?›
It depends on which figure you want. The federal income tax effective rate is income tax divided by gross income. The combined effective rate adds Social Security at 6.2 percent up to $184,500 of wages, plus Medicare at 1.45 percent (with an additional 0.9 percent on wages above $200,000). For a $75,000 single filer the federal income tax effective rate is roughly 10 percent, while the combined federal rate including FICA is roughly 17.9 percent.
Q.5What is the effective tax rate on $100,000?›
A single filer earning $100,000 in 2026 with the standard deduction has $83,900 of taxable income. The arithmetic: $12,400 at 10 percent, $38,000 at 12 percent, and $33,500 at 22 percent. Total federal income tax is roughly $13,170, an effective rate of about 13.2 percent. Add FICA of 7.65 percent and the combined federal effective rate is about 20.8 percent. State income tax adds another 0 to 10 percentage points depending on where you live.
Q.6How big is the standard deduction in 2026?›
The 2026 standard deduction (IRS Revenue Procedure 2025-32) is $16,100 for single filers, $32,200 for married filing jointly, and $24,150 for head of household. It is the most powerful single tool for lowering your effective rate at low and middle incomes, because it removes the entire amount from your taxable income before any bracket math runs.
Q.7Are effective tax rate and average tax rate the same?›
Yes. Tax software and the IRS prefer 'effective tax rate,' while economics textbooks tend to use 'average tax rate.' Both mean total tax paid divided by total income. Both contrast with the marginal rate, which is the rate on the next dollar earned. Watch the denominator: some sources divide by adjusted gross income or taxable income instead of gross, which produces a higher number.
Q.8How do long-term capital gains affect my rate?›
Long-term capital gains (held more than a year) get preferential rates: 0 percent for low incomes, 15 percent through most middle and upper-middle incomes, and 20 percent above $533,400 (single, 2026). They lower your blended effective rate compared to the same dollar earned as wages. Short-term gains, by contrast, are stacked on top of ordinary income and taxed at your ordinary marginal bracket.