Income Tax Calculator
Estimate your US federal income tax using 2024 tax brackets. See your effective rate, marginal rate, and bracket-by-bracket breakdown. See also Sales Tax Calculator and Salary Calculator.
How to Calculate Federal Income Tax
US federal income tax uses a progressive bracket system. First, subtract the standard deduction from your gross income to get taxable income. Then apply each tax rate only to the income that falls within that bracket. For example, a single filer earning $75,000 in 2024 has a standard deduction of $14,600, leaving $60,400 in taxable income. The first $11,600 is taxed at 10%, the next $35,550 at 12%, and the remaining $13,250 at 22%.
Income Tax Formula
Taxable Income = Gross Income − Standard Deduction
Tax = Σ (Income in Bracket × Bracket Rate)
Effective Rate = Total Tax / Gross Income × 100
Marginal Rate = Rate of the highest bracket reached
Example
Gross Income: $75,000 (Single filer, 2024)
Standard Deduction: $14,600
Taxable Income: $75,000 − $14,600 = $60,400
$11,600 × 10% = $1,160.00
$35,550 × 12% = $4,266.00
$13,250 × 22% = $2,915.00
Total Tax = $8,341.00
Effective Rate = 11.12%
2024 Federal Tax Brackets Reference
| Rate | Single | Married Filing Jointly | Head of Household |
|---|---|---|---|
| 10% | $0 – $11,600 | $0 – $23,200 | $0 – $16,550 |
| 12% | $11,601 – $47,150 | $23,201 – $94,300 | $16,551 – $63,100 |
| 22% | $47,151 – $100,525 | $94,301 – $201,050 | $63,101 – $100,500 |
| 24% | $100,526 – $191,950 | $201,051 – $383,900 | $100,501 – $191,950 |
| 32% | $191,951 – $243,725 | $383,901 – $487,450 | $191,951 – $243,700 |
| 35% | $243,726 – $609,350 | $487,451 – $731,200 | $243,701 – $609,350 |
| 37% | $609,351+ | $731,201+ | $609,351+ |
Frequently Asked Questions
What is the difference between marginal and effective tax rate?
Your marginal rate is the rate on your last dollar of income — the highest bracket you reach. Your effective rate is the average rate across all your income (total tax / gross income). The effective rate is always lower than the marginal rate because lower brackets are taxed at lower rates.
What is the standard deduction for 2024?
For 2024, the standard deduction is $14,600 for single filers, $29,200 for married filing jointly, and $21,900 for head of household. Taxpayers age 65+ or blind get an additional deduction.
Does this include state income tax?
No, this calculator only estimates federal income tax. State income tax varies widely — some states have no income tax (Texas, Florida, Nevada), while others have rates up to 13.3% (California). You would need to add state tax separately.
Does this include FICA taxes?
No. FICA taxes (Social Security at 6.2% and Medicare at 1.45%) are separate from income tax. For 2024, Social Security tax applies to the first $168,600 of earnings. An additional 0.9% Medicare tax applies to earnings over $200,000 for single filers.
Solved Examples
Example 1: Calculating federal income tax (Single filer, 2024)
Solution:
Gross income = $85,000, Standard deduction = $14,600
Taxable income = $85,000 - $14,600 = $70,400
Tax on first $11,600 at 10% = $1,160
Tax on $11,601-$47,150 at 12% = $4,266
Tax on $47,151-$70,400 at 22% = $5,115
Total federal tax = $1,160 + $4,266 + $5,115 = $10,541
Effective tax rate = $10,541 / $85,000 = 12.4%
Answer: Federal tax = $10,541 (12.4% effective rate, despite being in the 22% bracket).
Example 2: Marginal vs effective tax rate comparison
Solution:
Taxable income = $180,000 (Single)
Falls in 32% bracket ($191,950+ threshold)
Actually in 24% bracket (up to $201,050 for 2024)
Tax: 10% on first $11,600 + 12% on next $35,550 + 22% on next $53,375 + 24% on remaining $79,475
= $1,160 + $4,266 + $11,743 + $19,074 = $36,243
Effective rate = $36,243 / $180,000 = 20.1%
Answer: Marginal rate is 24%, but effective rate is only 20.1% due to progressive brackets.
Example 3: Impact of a $6,500 IRA deduction
Solution:
Income = $75,000, Standard deduction applied, in 22% bracket
Traditional IRA contribution = $6,500 (deductible)
Tax savings = $6,500 × 22% (marginal rate) = $1,430
Effective cost of $6,500 contribution = $6,500 - $1,430 = $5,070
Answer: The IRA saves $1,430 in taxes — your $6,500 investment only costs you $5,070 out of pocket.
Practice Questions
Try these on your own:
- Taxable income = $45,000 (single). Calculate federal tax using 2024 brackets. (Answer: ≈$5,147)
- If you earn $100,000 and contribute $22,500 to a 401(k), what is your taxable income after standard deduction? (Answer: $62,900)
- Your marginal rate is 24%. How much tax do you save by donating $5,000 to charity (itemizing)? (Answer: $1,200)
- A married couple earns $150,000. Standard deduction = $29,200. What bracket are they in? (Answer: 22% bracket)
- You get a $10,000 raise pushing you from 12% to 22% bracket. How much extra tax on just the raise? (Answer: $2,200, not $10,000 × 22%)
Common Mistakes to Avoid
The most widespread misconception is that moving into a higher tax bracket means ALL your income is taxed at the higher rate. In reality, only the income above the bracket threshold is taxed at the higher rate — it's a progressive system. Another mistake is confusing tax deductions with tax credits: a $1,000 deduction saves you $1,000 × your marginal rate (e.g., $220 at 22%), while a $1,000 tax credit reduces your tax bill by the full $1,000. Many people also forget that Social Security and Medicare taxes (FICA, 7.65%) are separate from income tax and apply to all earned income up to the cap. Failing to account for state income taxes (which range from 0% to 13.3%) when comparing job offers in different states is another costly oversight. Finally, not adjusting withholdings after major life changes (marriage, children, job change) can lead to large unexpected tax bills or excessive refunds.
Key Takeaways
- The US uses progressive tax brackets — only income within each bracket is taxed at that rate.
- Effective tax rate (total tax / total income) is always lower than your marginal bracket rate.
- Deductions reduce taxable income; credits directly reduce tax owed (credits are more valuable dollar-for-dollar).
- Pre-tax contributions (401k, traditional IRA, HSA) reduce your current taxable income at your marginal rate.
- FICA taxes (7.65%) apply separately: 6.2% Social Security (up to $168,600) + 1.45% Medicare (no cap).
- State income taxes add 0-13.3% on top of federal — factor these into any relocation or job comparison.