Tax & Withholding Calculators

The U.S. tax code touches nearly every financial decision a household makes. CalcFi's tax calculator stack pulls directly from IRS publications and state Department of Revenue bracket files to give you accurate federal + state liability in under a minute.

Federal bracket structure in 2026

The IRS publishes seven marginal brackets for 2026: 10%, 12%, 22%, 24%, 32%, 35%, and 37%^[1]. Only the income within each band is taxed at that band's rate — a common misconception is that hitting the next bracket re-taxes all earnings at the higher rate. The Tax Bracket Calculator visualizes exactly which dollars fall in which band.

Standard deduction vs itemizing

The 2026 standard deduction is $14,600 single / $29,200 married filing jointly. Itemizing beats the standard deduction only if SALT + mortgage interest + charitable + medical (above 7.5% AGI floor) exceeds those thresholds. Post-TCJA, ~87% of filers take the standard deduction per IRS SOI data.

State income tax: seven no-tax states, eight flat-tax states, rest progressive

Florida, Texas, Nevada, Washington, Tennessee, South Dakota, and Wyoming have no state income tax. Eight more (NC, CO, IL, IN, KY, MI, MA, PA, UT) have flat rates 3–5%. The remaining states run progressive brackets topping out at 13.3% in California^[5]. CalcFi's Income Tax Calculator fetches the active bracket file for any state.

FICA and self-employment tax

Wage earners pay 7.65% FICA (6.2% Social Security on income up to $168,600 in 2026 + 1.45% Medicare no cap)^[4]. Self-employed workers pay both halves = 15.3% on 92.35% of net SE income. Use the Self-Employed Tax calculator for quarterly-estimate planning.

Capital gains

Long-term capital gains (held >1 year) tax at 0%, 15%, or 20% federally depending on income. Short-term gains tax at ordinary income rates. High earners pay an additional 3.8% Net Investment Income Tax. States mostly tax capital gains as ordinary income; a few exceptions include Washington's 7% capital gains excise (stocks above $270k). The Capital Gains Tax calculator handles federal + state in one view.

Household tax burden varies by more than 10 percentage points of income across states. Here's how ten states compare for a $125,000 household in 2026, pulling from Tax Foundation data^[3] and state DOR brackets^[5].

Low-burden states

• Texas — 0% state income, 6.25% sales, 1.60% property. Total effective burden ~8% of income.
• Florida — 0% state income, 6.0% sales, 0.89% property with homestead. Total ~7%.
• Nevada — 0% state income, 6.85% sales, 0.48% property. Total ~7%.
• Washington — 0% state income (but 7% LTCG excise), 6.5% sales, 0.92% property. Total ~9%.
• Tennessee — 0% state income (Hall Tax repealed), 7.0% sales, 0.56% property. Total ~8%.

High-burden states

• California — 9.3% marginal at $125k, 7.25% sales, 0.75% property (Prop 13). Total ~14%.
• New York — 6.25% at $125k, 4.0% state sales (NYC adds 4.5%), 1.72% property. Total ~14% in NYC.
• New Jersey — 6.37% at $125k, 6.625% sales, 2.23% property. Total ~14%.
• Oregon — 9.0% at $125k, 0% sales, 0.93% property. Total ~11%.
• Hawaii — 8.25% at $125k, 4.0% excise (effectively sales), 0.28% property. Total ~10%.

Property tax often dominates the difference between comparable states. The CalcFi state-variant hubs at /hub/tax/[state] render the full 50-state comparison.

Several major TCJA provisions (2017) are scheduled to sunset at end of 2027 absent Congressional action. Households planning multi-year tax strategies should model both scenarios.

What sunsets January 1, 2027

• Standard deduction reverts to ~$8,300 single / ~$16,600 MFJ (half of 2026 levels).
• Top individual bracket reverts from 37% to 39.6%.
• Personal exemption of ~$4,900 returns.
• 20% QBI deduction for pass-through income expires.
• SALT cap ($10k) expires — full state tax deductibility returns for itemizers.
• Estate-tax exemption drops from ~$13.6M single / $27.2M married to ~$7M/$14M.

Strategic windows closing

Roth conversions at current lower brackets, gifting up to exemption, and QBI harvesting for pass-through business owners are all time-bounded. Run multi-year projections with Income Tax Calculator at both 2026 and post-sunset rates.

What isn't changing

Capital gains rates, the Net Investment Income Tax, FICA caps (indexed to wage growth), and standard retirement-account limits continue under current law.

CalcFi's 16 tax calculators cluster around three decision contexts:

Withholding / paycheck planning

• Will my W-4 withhold the right amount? → Tax Withholding
• What's my actual take-home? → Paycheck Calculator
• Payroll deductions by state? → Payroll Withholding

Annual filing

• What's my full liability? → Income Tax Calculator
• Which bracket am I in? → Tax Bracket Calculator
• Marginal vs effective rate? → Marginal vs Effective

Life events

• Sold a stock or home? → Capital Gains Tax
• Estate planning? → Estate Tax Calculator
• Self-employed? → Self-Employment Tax + QBI Deduction
• Home office? → Home Office Deduction
• IRS penalty owed? → IRS Penalty Calculator

Five strategies that consistently outperform do-nothing tax planning:

1. Roth conversion ladder

Convert traditional IRA/401k balances to Roth during low-income years (sabbatical, early retirement, gap year) to pay tax at lower brackets now vs higher brackets in retirement. Net tax arbitrage over 20 years: often $50k+ on a $500k traditional balance.

2. HSA triple-tax-advantage stacking

Health Savings Accounts are the only triple-tax-advantaged account: deductible contribution, tax-free growth, tax-free withdrawal for medical. Max out HSA before any other account beyond employer 401k match. 2026 limits: $4,300 self / $8,550 family.

3. Charitable bunching

Post-TCJA, fewer filers itemize. "Bunching" concentrates two to three years of charitable giving into a single tax year via donor-advised fund, crossing the itemization threshold that year and taking standard deduction in the others. Saves $1–5k annually for high-charitable-giving households.

4. Tax-loss harvesting

Selling losing positions to offset up to $3,000 of ordinary income per year (plus unlimited capital gains offset) is one of the few historically reliable free lunches in finance. Use the Tax Loss Harvesting calculator to size harvest opportunities in your portfolio.

5. Backdoor / mega-backdoor Roth

High earners phased out of direct Roth IRA can still contribute via non-deductible traditional IRA → immediate Roth conversion (backdoor) or via after-tax 401k → in-service Roth rollover (mega-backdoor, up to $46k/yr). See Backdoor Roth Calculator.

IRS Statistics of Income data shows the most common filing errors. Each is avoidable with a calculator-backed approach.

1. Under-withholding safe harbor miss

To avoid underpayment penalty, withhold at least 90% of current-year liability OR 100% of prior-year (110% if AGI >$150k). Use the Tax Withholding Calculator before October each year to verify.

2. Missing cost basis on sold investments

Brokerages report proceeds but often not basis for pre-2011 positions. Missing basis = tax on full sale price. Document every lot acquired.

3. Quarterly estimates with wrong base

Self-employed filers must make quarterly estimated payments by Apr 15, June 15, Sept 15, Jan 15. Using last year's number when current year is significantly higher triggers Form 2210 penalty.

4. Roth IRA income limit miss

2026 MAGI phase-out for direct Roth IRA contribution: $150k–$165k single / $236k–$246k MFJ. Over-contributing triggers 6% annual excise until withdrawn.

5. HSA rollover into FSA in same year

Having both an HSA and a general-purpose FSA in the same year disqualifies HSA contributions. Use limited-purpose FSA instead.

6. Not filing state returns after moving

Part-year resident returns are required in both old and new states when moving mid-year. Tax software sometimes misses this.