{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"electric-power"},"result":{"entity_type":"calculator","id":"electric-power","calculator_id":"electric-power","canonical_url":"https://tttkmbb.com/physics/electric-power","name":"Electric Power Calculator","title":"Electric Power Calculator – P = V·I, Current from Wattage, Energy in kWh and Running Cost","category":"physics","category_name":"Physics","tool_name":"calculate_electric_power","featured_mcp_tool":false,"description":"Computes electrical power from voltage and current (or the current drawn by a known power at a given voltage), the equivalent resistance, and, with hours of use and a tariff, the energy in kWh and its cost.","use_when":"You need the wattage or amperage of an appliance, whether it fits a circuit rating, or how much energy and money it uses over a period.","do_not_use_when":"The load has a power factor below 1 (motors, some electronics: P = V·I·cos φ), you only need V, I and R relations (use ohms-law), or you want a multi-appliance bill (use electricity-cost).","inputs":[{"name":"voltage_v","label":"Voltage","type":"number","unit":"V","required":true,"exclusive_min":0,"description":"Supply voltage in volts (e.g. 230 in Europe, 120 in North America, 12 for automotive).","example":230},{"name":"current_a","label":"Current","type":"number","unit":"A","required":false,"min":0,"description":"Current drawn in amperes. Give either current_a or power_w.","example":6.5},{"name":"power_w","label":"Power","type":"number","unit":"W","required":false,"min":0,"description":"Rated power in watts. Give either current_a or power_w."},{"name":"usage_hours","label":"Hours of use","type":"number","unit":"h","required":false,"min":0,"description":"Optional operating time; enables the energy output.","example":2},{"name":"price_per_kwh","label":"Electricity price","type":"number","unit":"per kWh","required":false,"min":0,"description":"Optional tariff in your currency per kilowatt-hour; enables the cost output.","example":0.3}],"outputs":[{"name":"power_w","label":"Power","type":"number","unit":"W","decimals":4,"description":"P = V × I."},{"name":"power_kw","label":"Power","type":"number","unit":"kW","decimals":6,"description":"Power in kilowatts."},{"name":"current_a","label":"Current","type":"number","unit":"A","decimals":4,"description":"I = P / V."},{"name":"resistance_ohm","label":"Equivalent resistance","type":"number","unit":"Ω","decimals":4,"description":"R = V / I for a purely resistive load."},{"name":"energy_kwh","label":"Energy used","type":"number","unit":"kWh","decimals":4,"description":"P × usage_hours / 1000 (only when usage_hours is given)."},{"name":"energy_cost","label":"Cost","type":"number","decimals":2,"description":"energy_kwh × price_per_kwh (only when usage_hours and price_per_kwh are given)."}],"input_schema":{"type":"object","properties":{"voltage_v":{"description":"Supply voltage in volts (e.g. 230 in Europe, 120 in North America, 12 for automotive). Unit: V.","type":"number","exclusiveMinimum":0,"examples":[230],"x-unit":"V"},"current_a":{"description":"Current drawn in amperes. Give either current_a or power_w. Unit: A.","type":"number","minimum":0,"examples":[6.5],"x-unit":"A"},"power_w":{"description":"Rated power in watts. Give either current_a or power_w. Unit: W.","type":"number","minimum":0,"x-unit":"W"},"usage_hours":{"description":"Optional operating time; enables the energy output. Unit: h.","type":"number","minimum":0,"examples":[2],"x-unit":"h"},"price_per_kwh":{"description":"Optional tariff in your currency per kilowatt-hour; enables the cost output. Unit: per kWh.","type":"number","minimum":0,"examples":[0.3],"x-unit":"per kWh"}},"additionalProperties":false,"required":["voltage_v"]},"output_schema":{"type":"object","properties":{"power_w":{"description":"P = V × I. Unit: W.","type":"number","x-unit":"W"},"power_kw":{"description":"Power in kilowatts. Unit: kW.","type":"number","x-unit":"kW"},"current_a":{"description":"I = P / V. Unit: A.","type":"number","x-unit":"A"},"resistance_ohm":{"description":"R = V / I for a purely resistive load. Unit: Ω.","type":"number","x-unit":"Ω"},"energy_kwh":{"description":"P × usage_hours / 1000 (only when usage_hours is given). Unit: kWh.","type":"number","x-unit":"kWh"},"energy_cost":{"description":"energy_kwh × price_per_kwh (only when usage_hours and price_per_kwh are given).","type":"number"}}},"formula":"power_w = voltage_v × current_a (or current_a = power_w / voltage_v); resistance_ohm = voltage_v / current_a; energy_kwh = power_w × usage_hours / 1000; energy_cost = energy_kwh × price_per_kwh","sources":[{"name":"HyperPhysics – Electric power","url":"http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elepow.html","type":"reference","retrieved_at":"2026-09-23"},{"name":"Wikipedia – Electric power","url":"https://en.wikipedia.org/wiki/Electric_power","type":"reference","retrieved_at":"2026-09-23"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"230 V, 6.5 A for 2 h at 0.30 per kWh","inputs":{"voltage_v":230,"current_a":6.5,"usage_hours":2,"price_per_kwh":0.3},"expected":{"power_w":1495,"power_kw":1.495,"current_a":6.5,"resistance_ohm":35.3846,"energy_kwh":2.99,"energy_cost":0.9},"url":"https://tttkmbb.com/api/v1/calculate/electric-power?voltage_v=230&current_a=6.5&usage_hours=2&price_per_kwh=0.3"},{"name":"1500 W heater on 120 V","inputs":{"voltage_v":120,"power_w":1500},"expected":{"power_w":1500,"current_a":12.5,"resistance_ohm":9.6},"url":"https://tttkmbb.com/api/v1/calculate/electric-power?voltage_v=120&power_w=1500"}],"faq":[{"q":"Is the nameplate wattage the actual consumption?","a":"It is the maximum rating. Thermostat-controlled appliances (heaters, fridges) draw it only part of the time, so real energy use is lower."},{"q":"What about three-phase or AC loads?","a":"For single-phase AC the formula gives apparent power (VA); real power is V·I·cos φ. Three-phase power is √3 × V_line × I × cos φ and is not covered here."}],"tags":["electric power","watts","amps to watts","kwh","electricity cost","appliance power"],"related":[{"calculator_id":"ohms-law","reason":"Voltage, current and resistance relations."},{"calculator_id":"electricity-cost","reason":"Running cost of several appliances over a period."},{"calculator_id":"work-power","reason":"Mechanical power from work and time."}],"links":{"html":"https://tttkmbb.com/physics/electric-power","markdown":"https://tttkmbb.com/physics/electric-power.md","json":"https://tttkmbb.com/physics/electric-power.json","api":"https://tttkmbb.com/api/v1/calculate/electric-power","schema":"https://tttkmbb.com/api/v1/calculators/electric-power","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-23"},"timestamp":"2026-09-23T23:27:56Z"}