Computes US federal income tax (2026 IRS brackets, post-OBBBA) plus an estimated state income tax, with a full progressive bracket breakdown. Example: { grossIncome: 95000, filingStatus: "single", stateCode: "CA" }. Estimate for guidance — 2026 rates from official sources (IRS/Tax Foundation/CRA/ATO/state revenue offices/HMRC).

Computes US take-home pay per pay period: federal withholding, Social Security, Medicare (+ Additional Medicare), state tax, and net pay, for salaried or hourly workers. Example: { payType: "salary", annualSalary: 80000, payFrequency: "biweekly", filingStatus: "single", stateCode: "TX" }. Estimate for guidance — 2026 rates from official sources (IRS/Tax Foundation/CRA/ATO/state revenue offices/HMRC).

Estimates annual/monthly US property tax from a home value and either a custom rate or a state's real 2026 effective property tax rate. Example: { homeValue: 350000, stateCode: "NJ" }. Estimate for guidance — 2026 rates from official sources (IRS/Tax Foundation/CRA/ATO/state revenue offices/HMRC).

Computes Canadian federal + provincial/territorial income tax, CPP/QPP (+ CPP2/QPP2), EI/QPIP, and net take-home pay for a given province, 2026 rates. Example: { grossIncome: 75000, provinceCode: "ON" }. Set compareAllProvinces: true to get every province/territory side by side. Estimate for guidance — 2026 rates from official sources (IRS/Tax Foundation/CRA/ATO/state revenue offices/HMRC).

Computes Australian resident income tax (2025-26 ATO brackets) plus Medicare levy, Medicare levy surcharge, LITO offset, and HELP/HECS repayment. Example: { taxableIncome: 95000, privateHospitalCover: true, hasHelpDebt: false }. Estimate for guidance — 2026 rates from official sources (IRS/Tax Foundation/CRA/ATO/state revenue offices/HMRC).

Computes Australian state/territory stamp duty on a property purchase, including first-home-buyer concessions and the foreign purchaser surcharge where applicable. Example: { propertyValue: 750000, stateCode: "NSW", firstHomeBuyer: false, foreignResident: false, principalResidence: true }. Set compareAllStates: true to compare every state/territory for the same property value. Estimate for guidance — 2026 rates from official sources (IRS/Tax Foundation/CRA/ATO/state revenue offices/HMRC).

Computes UK dividend tax using HMRC's stacking method (dividends sit on top of other income), including the tapered Personal Allowance and the £500 dividend allowance, with a year-over-year comparison. Example: { otherIncome: 40000, dividends: 15000, year: "2026/27" }. Estimate for guidance — 2026 rates from official sources (IRS/Tax Foundation/CRA/ATO/state revenue offices/HMRC).