Power Calculator

Solve for watts, kW, amps, volts, or power factor from any two known values. Core relations: P = V × I × PF, I = P ÷ (V × PF), and kW = (V × I × PF) ÷ 1,000. Supports DC, single-phase AC, and resistive loads with power factor correction.

Calculate balanced three-phase real power, apparent power, and line current with the √3 factor. Formulas: kW = (√3 × VLL × I × PF) ÷ 1,000, kVA = (√3 × VLL × I) ÷ 1,000, and Amps = (kVA × 1,000) ÷ (√3 × VLL). Supports line-to-line and line-to-neutral inputs.

Compute power factor from kW and kVA (PF = kW ÷ kVA), derive reactive power kVAR = √(kVA² − kW²), and convert between PF and phase angle with PF = cos θ. Flags low power factor below 0.90 and estimates penalty exposure where utilities charge PF penalties.

Size power factor correction capacitors with kVARcap = kW × (tan θ₁ − tan θ₂), where θ₁ is the existing phase angle and θ₂ is the target. Example: a 150 kW load corrected from 0.80 to 0.95 PF needs about 57 kVAR. Includes correction factor lookup tables and capacitor current estimation.

Estimate daily, monthly, and annual energy use with kWh = (Watts × Hours) ÷ 1,000, then multiply by the local tariff for cost. Run appliance-level scenarios, compare load profiles, and calculate simple payback for efficiency upgrades such as LED retrofits, PF correction, and motor replacements.

Cross-check connected loads against NEC Article 220 general lighting densities (3 VA/ft² for dwellings), demand factors, and the 2026 Article 120 relocation updates. Generate PDF calculation sheets showing inputs, formulas, results, and NEC references, and export to CSV for project files. All calculations run offline.