TaxArith editorial library
Understand the estimate before you use it
Thirty focused guides connect the rules inside all ten TaxArith calculators with realistic numbers and careful planning questions. Every article covers 2026 U.S. federal tax only.
Start with the calculation, follow a production-backed example, or focus on the decision the estimate is meant to support.
Fundamentals
Build a reliable mental model of the calculation.
Worked example
Follow production calculation logic through a realistic scenario.
Decision guide
Use an estimate carefully in a real planning decision.
Calculator 01
Tax Bracket
See how your taxable income is distributed across the 2026 federal tax brackets.
Open calculator- FundamentalsHow the 2026 Federal Tax Brackets Actually WorkBuild the right mental model for marginal brackets, taxable income, and effective federal tax rates.8 min
- Worked exampleA Tax-Bracket Walkthrough for an $85,000 Single FilerFollow income through adjustments, the standard deduction, bracket layers, and the final estimate.7 min
- Decision guideWhen Your Marginal Rate Is Useful—and When It Is NotUse a bracket estimate carefully when evaluating extra income, withholding, or a change in deductions.7 min
Calculator 02
Federal Income Tax
Estimate your 2026 federal income tax from ordinary income, qualified dividends, long-term capital gains, deductions, and credits.
Open calculator- FundamentalsFrom Gross Income to a 2026 Federal Income Tax EstimateUnderstand how ordinary income, preferential income, deductions, and credits move through the estimate.10 min
- Worked exampleFederal Income Tax Example: Wages, Dividends, and a Long-Term GainSee why mixed income is not taxed by multiplying one rate by the total.9 min
- Decision guideHow to Compare Federal Tax Scenarios Without Overreading the EstimateIdentify which changes deserve a new calculation and which missing facts can overturn the comparison.8 min
Calculator 03
Tax Refund
Estimate your 2026 federal tax refund or amount owed from income, deductions, credits, withholding, and tax payments.
Open calculator- FundamentalsA Tax Refund Is a Reconciliation, Not a Tax RateSeparate tax liability from withholding, payments, refundable credits, and the amount finally reconciled.8 min
- Worked exampleTax Refund Example: When Withholding Does Not Quite Cover the BillTrace a fictional filer’s tax, payments, and resulting amount owed without treating it as a filing promise.7 min
- Decision guideWhat to Review After a Large Refund or Amount Owed EstimateTurn the result into a document-checking and scenario-comparison process, not a snap withholding decision.8 min
Calculator 04
Self-Employment Tax
Estimate 2026 Social Security and Medicare self-employment tax, including the effect of covered wages.
Open calculator- FundamentalsHow 2026 Self-Employment Tax Is Built from Net ProfitFollow net profit through the net-earnings factor, Social Security wage base, Medicare tax, and deductible half.9 min
- Worked exampleSelf-Employment Tax Example for a Freelance DesignerSee how business revenue and expenses become net profit and then self-employment tax.8 min
- Decision guideUsing a Self-Employment Tax Estimate in a Cash-Flow PlanDecide what the estimate can reserve for and what still belongs in a full income-tax and payment plan.8 min
Calculator 05
Quarterly Estimated Tax
Plan 2026 federal estimated payments with safe-harbor comparisons, withholding, progress, and official due dates.
Open calculator- FundamentalsQuarterly Estimated Tax: Balance Due, Safe Harbor, and Due DatesUnderstand why the planning target can differ from projected total tax and why the periods are not equal quarters.10 min
- Worked exampleQuarterly Estimated Tax Example for a Consultant with WithholdingFollow projected income tax, withholding, prior-year tax, and payments into a safe-harbor plan.9 min
- Decision guideWhich Estimated-Tax Target Should You Plan Around?Compare current-year and prior-year targets while recognizing uneven income and penalty-analysis limits.9 min
Calculator 06
Capital Gains Tax
Estimate the 2026 federal tax impact of capital gains, losses, carryovers, qualified-dividend stacking, and optional NIIT.
Open calculator- FundamentalsCapital Gains: Netting Losses Before Applying Rate StacksUnderstand transaction gain, holding-period character, cross-netting, loss deductions, preferential rates, and optional NIIT.11 min
- Worked exampleCapital Gains Example: Two Sales, One Carryover, and NIITTrace short- and long-term transactions through netting, preferential brackets, and the optional NIIT layer.10 min
- Decision guideWhat to Compare Before You Sell an InvestmentUse sale scenarios to test basis, holding period, loss carryovers, income stacking, and NIIT assumptions.9 min
Calculator 07
Crypto Tax
Estimate the 2026 federal income-tax impact of taxable crypto dispositions, capital netting, loss carryovers, and long-term rate stacking.
Open calculator- FundamentalsCrypto Tax Starts with Each Taxable DispositionConnect cash sales, swaps, and spending to amount realized, basis, holding period, and capital netting.10 min
- Worked exampleCrypto Tax Example: A Long-Term Sale and a Short-Term SwapSee how two different digital-asset dispositions keep their own dates and character before netting.9 min
- Decision guideWhen a Crypto Tax Estimate Needs Better Transaction DataDecide whether a high-level estimate is enough or lot-level records and classification work are still required.9 min
Calculator 08
Standard vs. Itemized
Compare 2026 standard and itemized deductions, taxable income, and estimated federal income tax after category limits.
Open calculator- FundamentalsStandard vs. Itemized Is a Tax Comparison, Not Just a Receipt TotalSee how category limits, AGI floors, preferential income, and filing rules affect both deduction paths.11 min
- Worked exampleDeduction Example: A Homeowner Near the Itemizing Break-Even PointFollow medical, SALT, mortgage-interest, and charitable amounts into two complete tax paths.10 min
- Decision guideShould You Gather the Records to Itemize?Use the comparison to prioritize documentation and test uncertainty without assuming every payment is deductible.9 min
Calculator 09
Tax Loss Harvesting
Compare the 2026 federal tax effect of selected capital-loss sales after transaction costs, wash-sale adjustments, netting, deductions, and carryforward.
Open calculator- FundamentalsTax-Loss Harvesting: The Tax Result Comes After Netting and Wash-Sale ReviewUnderstand how an allowed realized loss moves through gains, the annual deduction, carryforward, and the full tax comparison.11 min
- Worked exampleTax-Loss Harvesting Example with a Partial Wash-Sale AdjustmentTrace two proposed sales through allowed loss, gain offsets, the annual deduction, carryforward, and tax savings.10 min
- Decision guideA Tax Benefit Is Not the Same as a Good Harvesting TradeCompare tax timing with wash-sale exposure, portfolio consequences, transaction costs, and future carryforward use.9 min
Calculator 10
Child Tax Credit
Estimate 2026 federal CTC, ODC, refundable ACTC, MAGI phaseout, tax-liability limits, and dependent screening.
Open calculator- FundamentalsCTC, ODC, and ACTC: Three Limits in One EstimateUnderstand dependent screening, MAGI phaseout, tax-liability limits, and the separate refundable ACTC calculation.11 min
- Worked exampleChild Tax Credit Example for a Family with Two Different DependentsSee one CTC child and one ODC dependent move through screening, phaseout, tax liability, and refundability.10 min
- Decision guideWhat to Verify Before Relying on a Dependent-Credit EstimateTurn eligibility flags into a focused review of identification, dependency, custody, income, and tax-liability facts.9 min
TaxArith provides informational estimates for the 2026 U.S. federal tax year. The guides and calculators do not cover state or local tax, prepare a return, determine eligibility, or replace current IRS materials or advice from a qualified professional.