Home Systems & Utilities

Reproduce one source-labelled electrical load schedule from connected volt-amperes and explicitly copied line multipliers—without choosing code factors or sizing a service, feeder, conductor or breaker.

Audit one documented protection-selection record from source-labelled current components, an explicit multiplier, an already selected device rating, and a documented conductor ampacity—without choosing a breaker or declaring compliance.

Calculate percentages in seven modes with visible formulas, strict input validation, signed percentage change, and symmetric percentage difference.

Audit voltage-drop arithmetic for one source-selected candidate conductor using documented impedance, path and units—without selecting AWG, ampacity, an allowable drop or code compliance.

Audit one documented series circuit path from source-labelled segment currents, lengths, path multipliers and effective impedances—without assuming copper, choosing wire size or applying a pass/fail threshold.

Convert square meters to square feet. Area conversion for real estate and flooring. Free unit converter with precise, instant browser-based conversions — no

Simple in-browser notepad with auto-save. Write quick notes that persist in your browser. Download as text file. No signup needed.

Calculate an entered utility bill reduction and simple payback, or compare observed bill averages without assuming what caused the change.

Estimate heating and cooling electricity from documented thermal loads, equivalent seasonal hours, seasonal efficiency ratings and an entered tariff.

Compare the same entered heating demand using explicit equivalent full-load hours, seasonal heat-pump efficiency, furnace AFUE, tariffs and other annual costs.

Build an installed quote, compare lifetime costs and calculate material packs. Separate payment-day cash from later reimbursements using your project records.

Reconcile one completed peak-hour hot-water demand with one exact storage or non-flow-activated water-heater model's source-owned First-Hour Rating.

Compare documented annual electricity use for two appliances using one local rate, entered upgrade cost, and explicit planning horizon.

Compare subscription and phone plan cash costs, including prepaid bills, promotions, fees, devices and switching costs. Save and restore your draft.

Estimate appliance kWh and cost by day, week, average month, current calendar month, and year, with an optional regional CO₂ factor.