Total 2026 federal tax as a sole proprietor / LLC vs S-corp vs C-corp for the same profit — SE tax vs FICA vs 21% corporate tax with qualified-dividend double taxation — ranked to the lowest.

S-corp reasonable-salary employment-tax saving: SE tax a sole proprietor pays on all profit vs FICA an S-corp pays on just the salary, with the distribution that escapes self-employment tax.

Break-even units and revenue (CVP): where contribution margin covers fixed costs.

Sale price after one or more stacked percentage discounts (applied sequentially, not summed) plus an optional flat amount off.

Margin, markup, and profit from cost — give cost plus any one of price, target margin %, or markup %, and it solves the rest.

Seller fees and net payout for Amazon, eBay, and Etsy at their verified 2026 standard fee schedules (Amazon referral %, eBay final value fee, Etsy listing + transaction + processing).

Order total from subtotal, discount, tax rate, and shipping — tax excludes shipping by default (toggle with taxShipping).

Payment-processor fee and net received for Stripe, PayPal, and Square at their verified 2026 standard US rates — or reverse gross-up (what to charge to net a target).

ROI %, ROAS, profit, and profit margin from revenue and cost (e.g. ad spend).

US sales tax — add or remove tax using the verified 2026 STATE base rate for any state + DC, plus an optional local rate. Flags gross-receipts states (HI/NM) and local-only states (AK).

Tip amount, total, and per-person split for a restaurant bill.

VAT / GST for 16 major economies (UK, EU, Australia, Canada, Japan, Singapore, UAE, India, and more) at the verified 2026 standard rate — add or remove.

Convert between APR and APY at any compounding frequency (or continuous).

Impermanent loss for a 50/50 constant-product LP position vs simply holding, given the price change of the volatile asset.

Liquidation price for a leveraged long or short (isolated margin), plus the % move to liquidation.

Match a crypto sale against buy lots (FIFO / LIFO / HIFO), returning realized gain/loss split short- vs long-term (IRS >365-day rule) plus the remaining lots.

Rank up to 10 stablecoin/yield options by projected return over a horizon at each stated APY.

Bond current yield and yield-to-maturity from face value, coupon, market price, and maturity — with the premium/discount/par classification.

Net present value and internal rate of return for a cash-flow series (index 0 = today, usually a negative outlay), plus the profitability index and an accept/reject call.

Amortized monthly payment, total interest, and a year-by-year balance schedule for any loan.

True APR (Reg Z / TILA) from the note rate plus financed fees — the real cost of borrowing.

Auto-loan payment including state sales tax (verified 2026 rates), trade-in credit, down payment, and fees.

Compare 2–6 loan offers by true total cost (payments + fees) and rank them.

Debt-to-income ratio — front-end and back-end — with pass/fail against your (or the conventional 28/36) limits.

How much time and interest an extra monthly payment saves on a loan.

HELOC payments: interest-only during the draw period and the amortizing payment when repayment begins (the payment jump).

Full monthly mortgage payment (PITI): principal & interest, property tax, insurance, PMI (auto when LTV > 80%), and HOA.

Whether buying discount points pays off: monthly savings from the rate buydown and the break-even month.

Refinance analysis: new payment, monthly savings, months to break even on closing costs, and lifetime interest saved.

LLC formation cost for any US state + DC: filing fee, annual/biennial report, franchise tax, publication requirements — Year-1 and 5-year totals from each state's own 2026 fee schedule.

Self-employed mortgage affordability: 2-year income averaging with add-backs, the declining-income rule, front/back DTI limits, PMI-aware max-price solve.

US net-paycheck breakdown for any of 51 jurisdictions: 2026 federal brackets, FICA (SS wage base $184,500, additional Medicare), and state income tax. Golden-vector verified.

Max home price a W-2 buyer can afford from income and debts, using front/back DTI limits and a PMI-aware price solve.

Adjustable-rate mortgage payment shock: the payment before and after the first reset, and the increase.

Rental property returns: cap rate (unleveraged), cash-on-cash (leveraged), gross rent multiplier, and the 1% rule.

Monthly PMI cost and the month it auto-cancels (at 78% of original value, per the Homeowners Protection Act).

Rent vs buy over a horizon: year-by-year renting cost vs net cost of owning (crediting equity + appreciation, net of selling costs), with the break-even year.

Full debt-payoff report: avalanche vs snowball simulated month-by-month with debt rollover — payoff order, debt-free month, total interest, and the exact gap between strategies.

All 51 US jurisdictions ranked by true 5-year LLC cost — filing, reports, franchise taxes, publication requirements — with per-state notes.

The same salary across all 51 US jurisdictions, ranked by net take-home — the relocation what-if in one call, with per-state tax detail and the best-to-worst annual spread.

Retirement-readiness projection: your savings grown to retirement age, the nest egg the 4%-rule requires for your target income, the surplus or gap, and the extra monthly contribution to close it.

Full 2026 tax estimate in one call: federal income tax + self-employment tax + employee FICA + state income tax, from wages, self-employment income, and other income — with the component breakdown, effective and marginal rates, and after-tax income.

401(k) contribution vs the 2026 limits (incl. age 50+ and 60–63 catch-ups) plus the employer match, capped at the §415(c) total.

2026 HSA or health-FSA contribution limit and income-tax savings — HSA self/family limits + age-55 catch-up + HDHP deductible/OOP bounds, or the FSA salary-reduction limit + carryover.

2026 IRA / Roth contribution limit for your situation — including the Roth MAGI phase-out and traditional-deduction phase-out (if covered by a workplace plan).

Required Minimum Distribution from a traditional IRA/401(k) using the IRS Uniform Lifetime Table — the amount you must withdraw at your age, given the prior year-end balance. RMDs begin at 73 (SECURE 2.0).

Federal tax cost of a Roth conversion in one year: the extra income tax from stacking the converted amount on top of your other taxable income, with the marginal rate before and after.

Social Security monthly benefit estimate from your AIME: the 2026 PIA bend-point formula plus the claim-age adjustment (62 pays 70%, FRA 67 pays 100%, 70 pays 124%).

Take-home comparison of the same pay as a W-2 employee vs a 1099 contractor — employee FICA vs self-employment tax (with the half-SE deduction) — and the higher contractor rate needed to match.

Withholding and net take-home on a bonus/commission using the 2026 federal supplemental-wage rate (22% flat; 37% on cumulative supplemental wages over $1M), plus FICA and an optional state supplemental rate.