# kW Calculator > Free kilowatt calculator and electrical power converter. Converts kilowatts to amps, horsepower, kVA, kWh and BTU/hr for DC, single-phase and three-phase circuits, showing the formula behind every result. kwcalculator.com is a static reference site built around one live calculator. Every conversion on the site is computed from published electrical formulas, and each page states the formula it used with the reader's own values substituted into it. Values described as typical are labelled as reference estimates rather than measurements. The site is informational: it does not give installation guidance, and it points to a licensed electrician for work that has to meet an electrical code. ## Main tool - [kW Calculator](https://kwcalculator.com/): The homepage calculator converts between kilowatts and amps for DC, AC single-phase, and AC three-phase circuits in both line-to-line and line-to-neutral form, with apparent power (kVA) and reactive power (kVAR) shown alongside every result. ## Conversion pages - [Amps to Kilowatts Calculator: From a Clamp Reading](https://kwcalculator.com/amps-to-kilowatts): Convert a clamp-meter amp reading into real kilowatts for DC, single-phase and three-phase circuits, power factor included, formula shown for every result. - [Horsepower to Kilowatts Calculator (Shaft & Input kW)](https://kwcalculator.com/horsepower-to-kilowatts): Convert motor horsepower to kilowatts, then divide by efficiency to find the electrical input power a compressor or motor actually draws from the panel. - [Kilowatts to Amps Calculator: Size Any Circuit Fast](https://kwcalculator.com/kilowatts-to-amps): Convert kilowatts to amps for DC, single-phase and three-phase circuits, formula shown for every result, built for sizing a breaker from a known kW load. - [Kilowatts to BTU/hr Calculator: kW to BTU for HVAC](https://kwcalculator.com/kilowatts-to-btu): Convert kilowatts to BTU per hour for HVAC sizing, formula shown for every result, with a reference table of common mini-split and heat pump ratings in kW. - [Kilowatts to Horsepower Calculator: Motor kW to HP](https://kwcalculator.com/kilowatts-to-horsepower): Convert a kW motor rating to horsepower instantly, with the 0.7457 constant shown, for matching IEC kW nameplates to NEMA HP motor specs. - [Kilowatts to Kilowatt-Hours Calculator: kW into kWh](https://kwcalculator.com/kilowatts-to-kilowatt-hours): Turn a kilowatt rating and a run-time into a kilowatt-hour total. Enter kW and hours per day to get daily and monthly kWh for pumps, heaters and chargers. - [Kilowatts to Volts Calculator: Solve Unknown Voltage](https://kwcalculator.com/kilowatts-to-volts): Calculate voltage from a known kilowatt load and a measured current, power factor included, for a circuit with no voltage rating on hand. - [kVA to Kilowatts Calculator: UPS & Generator Sizing](https://kwcalculator.com/kva-to-kilowatts): Convert kVA to kW for UPS units, generators and transformer nameplates using the actual power factor, with a worked 60 kVA example and reference table. - [Watts to Kilowatts Calculator: Convert W to kW Fast](https://kwcalculator.com/watts-to-kilowatts): Convert watts to kilowatts by dividing by 1,000, enter any wattage for an instant kW result, plus a reference table of common household device wattages. ## Concept and reference pages - [Apparent vs Reactive vs Real Power: kVA, kVAR and kW](https://kwcalculator.com/apparent-reactive-power): See how real power (kW), apparent power (kVA) and reactive power (kVAR) relate through the power triangle, with a worked 40 kW example. - [Electrical Power Formulas: Ohm, Watt, kW & kVA Guide](https://kwcalculator.com/electrical-power-formulas): Every core kilowatt formula on one scannable sheet: Ohm - [EV Charging Power Calculator: L1, L2 & DC Fast Time](https://kwcalculator.com/ev-charging-power): Compare Level 1, Level 2, and DC fast charging power in kW, then turn a battery size, state of charge, and charger efficiency into an actual charge time. - [Generator Sizing Calculator: Running vs. Starting Watts](https://kwcalculator.com/generator-sizing): Size a home backup generator from real appliance loads: running watts plus the worst motor-starting surge, converted into a continuous kW rating. - [Home Electricity Use Calculator: See Where Your kWh Go](https://kwcalculator.com/home-energy-use): Check off the appliances running in your home to estimate daily and monthly kWh use, built from the typical wattages in the table below. - [Kilowatt-Hour Cost Calculator: What a Load Costs You](https://kwcalculator.com/kilowatt-hour-cost): Turn a kW load and a run-time into a dollar figure: daily, monthly and annual cost, plus why a flat $/kWh rate misses both time-of-use and tiered pricing. - [Load Calculation Basics: Connected vs. Demand Load](https://kwcalculator.com/load-calculation-basics): A general-reference walkthrough of NEC Article 220 load calculations: connected load, tiered demand factors, and a worked example from VA down to amps. - [Motor Full-Load Current Calculator: NEC FLA Reference](https://kwcalculator.com/motor-full-load-current): Estimate a motor - [Power Factor Correction Calculator: Capacitor Sizing](https://kwcalculator.com/power-factor): Learn how capacitor banks correct power factor, what a utility PF surcharge looks like on a bill, and size correction kVAR with a worked 80 kW example. - [Solar System Size Calculator: Panels & Inverter kW](https://kwcalculator.com/solar-system-size): Turn daily kWh usage, peak sun hours, and system losses into a required array size, panel count, and inverter range, live calculator and worked example. - [Three-Phase Power Explained: Delta, Wye & Formulas](https://kwcalculator.com/three-phase-power): How delta and wye differ, why line-to-line voltage is √3 times line-to-neutral, an international voltage table, and a worked 75 kW compressor example. ## Translations The homepage is published in 18 languages. Supporting pages are English only. - https://kwcalculator.com/ - https://kwcalculator.com/es - https://kwcalculator.com/fr - https://kwcalculator.com/de - https://kwcalculator.com/pt - https://kwcalculator.com/it - https://kwcalculator.com/ru - https://kwcalculator.com/ja - https://kwcalculator.com/ko - https://kwcalculator.com/hi - https://kwcalculator.com/bn - https://kwcalculator.com/ar - https://kwcalculator.com/tr - https://kwcalculator.com/id - https://kwcalculator.com/ms - https://kwcalculator.com/pl - https://kwcalculator.com/sv - https://kwcalculator.com/bg ## Notes for citation - Constants used site-wide: 1 horsepower = 0.7457 kW (mechanical), 1 kW = 3412.14 BTU/hr, 1 ton of refrigeration = 3.516853 kW, three-phase multiplier = 1.7320508 (square root of 3). - Formulas: A = (kW x 1000) / (V x PF) single-phase; A = (kW x 1000) / (1.732 x V x PF) three-phase line-to-line; A = (kW x 1000) / (3 x V x PF) three-phase line-to-neutral; kVA squared = kW squared + kVAR squared. - The site publishes no ratings, no review counts, and no user numbers.