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Core personal income tax math: graduated bracket liability, rate measurement, taxable income build-up, refunds and capital gains…
Tax math specific to freelancers, contractors and small business owners: SE tax, quarterly installments, entity choice and the…
Cost recovery on business and rental assets plus the property tax and recapture math that follows them. Used by CPAs, real estate…
Consumption tax math in both directions plus cross-border duty and import tax. Used by retailers, e-commerce sellers, bookkeepers…
Everything between gross pay and the net on the check: federal withholding, FICA, employer unemployment tax, gross-ups and…
Wage and hour math governed by the FLSA and state rules: overtime and double time, blended regular rates, timecards, salary…
The payroll-linked benefit accounts and taxable fringe benefits that change take-home pay: HSA, FSA, dependent care, 401(k)…
Consumer-side insurance math: what a health plan will actually cost after cost sharing and subsidies, and how much life or…
Underwriting and claims math on the commercial and property side: workers comp rating, coinsurance clauses, actual cash value…
Most used in tax, payroll & insurance
- Progressive Tax Bracket CalculatorIRC §1 graduated rate schedule (Rev. Proc. 2025-32)Enter your taxable income and this calculator walks it up the federal graduated rate schedule one bracket at a time, showing…
- Marginal vs Effective Tax Rate CalculatorIRC §1 rate schedules with IRC §§3101 and 1401 payroll ratesTwo rates describe the same tax bill and they answer different questions. Your effective rate is total tax divided by income —…
- Taxable Income CalculatorForm 1040 income and deduction flow (IRC §§62, 63, 199A)Taxable income is not your salary and it is not your AGI — it is the figure on line 15 of Form 1040, and it is the only income…
- Income Tax Refund Estimator CalculatorForm 1040 payments and refund flow (IRC §§31, 6402, 6654)A refund is not a bonus and a balance due is not a penalty — both are just the difference between what you owed and what you…
- Capital Gains Tax CalculatorIRC §1(h) capital gain rates and §1411 net investment income taxSelling an asset creates a gain equal to proceeds less your adjusted basis less selling costs, and how that gain is taxed…
- Quarterly Estimated Tax CalculatorIRC §6654 estimated tax; Form 1040-ESIncome without withholding has to be paid for as you earn it, in four instalments, or the IRS charges interest on the…
- Home Office Deduction CalculatorIRC §280A; simplified method under Rev. Proc. 2013-13; Form 8829There are two ways to deduct a home office and they can differ by thousands of dollars. The simplified method pays $5 per…
- Business Mileage Deduction CalculatorIRS standard mileage rates (annual notice); IRC §170(i) charitable rateYou can deduct a business vehicle two ways, and you have to pick one. The standard mileage method multiplies business miles by…
- Rental Property Depreciation CalculatorMACRS GDS: 27.5-year residential / 39-year nonresidential, mid-month conventionDepreciation is the largest deduction most rental owners take and the one most often computed wrongly, because three things…
- Property Tax Mill Rate CalculatorAd valorem property tax; mill = $1 per $1,000 of taxable valueA property tax bill is three numbers you rarely see together: the assessor's opinion of value, the fraction of that value your…
- Sales Tax CalculatorState and local sales and use tax; sourcing under Wayfair (2018)Sales tax in the United States is almost never one rate. A single purchase can carry a state rate, a county rate, a city rate…
- Reverse Sales Tax CalculatorState and local sales and use tax; tax-inclusive to tax-exclusive conversionYou have a receipt total and you need the price before tax — for an expense report, a bookkeeping entry, or a reimbursement…