{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"voltage-divider"},"result":{"entity_type":"calculator","id":"voltage-divider","calculator_id":"voltage-divider","canonical_url":"https://tttkmbb.com/engineering/voltage-divider","name":"Voltage Divider Calculator","title":"Voltage Divider Calculator – Output Voltage, Current and Resistor Power for R1/R2, or Solve R2","category":"engineering","category_name":"Engineering & Automotive","tool_name":"calculate_voltage_divider","featured_mcp_tool":false,"description":"Computes the output voltage of a two-resistor divider (Vout = Vin·R2/(R1+R2)), the current through the chain and the power in each resistor, or solves for R2 when a target output voltage is given.","use_when":"You need the voltage at the junction of two series resistors, the R2 that produces a target voltage, or the power each resistor must handle.","do_not_use_when":"The output is loaded by a low-impedance load (the load parallels R2 and lowers Vout), you need a regulated supply, or you are limiting LED current (use led-resistor).","inputs":[{"name":"input_voltage_v","label":"Input voltage","type":"number","unit":"V","required":true,"max":100000,"exclusive_min":0,"description":"Voltage Vin applied across R1 + R2.","example":12},{"name":"r1_ohm","label":"R1 (top resistor)","type":"number","unit":"Ω","required":true,"exclusive_min":0,"description":"Resistor between Vin and the output node, in ohms (1 kΩ = 1000).","example":10000},{"name":"r2_ohm","label":"R2 (bottom resistor)","type":"number","unit":"Ω","required":false,"exclusive_min":0,"description":"Resistor between the output node and ground. Omit and give target_output_voltage_v to solve for it.","example":4700},{"name":"target_output_voltage_v","label":"Target output voltage","type":"number","unit":"V","required":false,"exclusive_min":0,"description":"Desired Vout; must be below input_voltage_v. Give either this or r2_ohm."}],"outputs":[{"name":"solved_for","label":"Solved for","type":"string","decimals":4,"description":"output_voltage_v when R2 was given, r2_ohm when the target voltage was given."},{"name":"output_voltage_v","label":"Output voltage","type":"number","unit":"V","decimals":4,"description":"Vout = Vin × R2 / (R1 + R2) with no load."},{"name":"r2_ohm","label":"R2","type":"number","unit":"Ω","decimals":2,"description":"Bottom resistor (computed as R1 × Vout / (Vin − Vout) when solving)."},{"name":"division_ratio","label":"Division ratio","type":"number","decimals":6,"description":"Vout / Vin = R2 / (R1 + R2)."},{"name":"current_ma","label":"Divider current","type":"number","unit":"mA","decimals":4,"description":"I = Vin / (R1 + R2), the quiescent current drawn from the source."},{"name":"power_r1_w","label":"Power in R1","type":"number","unit":"W","decimals":6,"description":"I² × R1."},{"name":"power_r2_w","label":"Power in R2","type":"number","unit":"W","decimals":6,"description":"I² × R2."},{"name":"total_power_w","label":"Total power","type":"number","unit":"W","decimals":6,"description":"Vin × I."},{"name":"output_impedance_ohm","label":"Output impedance","type":"number","unit":"Ω","decimals":2,"description":"Thévenin source resistance seen by a load: R1 ∥ R2 = R1 × R2 / (R1 + R2)."}],"input_schema":{"type":"object","properties":{"input_voltage_v":{"description":"Voltage Vin applied across R1 + R2. Unit: V.","type":"number","maximum":100000,"exclusiveMinimum":0,"examples":[12],"x-unit":"V"},"r1_ohm":{"description":"Resistor between Vin and the output node, in ohms (1 kΩ = 1000). Unit: Ω.","type":"number","exclusiveMinimum":0,"examples":[10000],"x-unit":"Ω"},"r2_ohm":{"description":"Resistor between the output node and ground. Omit and give target_output_voltage_v to solve for it. Unit: Ω.","type":"number","exclusiveMinimum":0,"examples":[4700],"x-unit":"Ω"},"target_output_voltage_v":{"description":"Desired Vout; must be below input_voltage_v. Give either this or r2_ohm. Unit: V.","type":"number","exclusiveMinimum":0,"x-unit":"V"}},"additionalProperties":false,"required":["input_voltage_v","r1_ohm"]},"output_schema":{"type":"object","properties":{"solved_for":{"description":"output_voltage_v when R2 was given, r2_ohm when the target voltage was given.","type":"string"},"output_voltage_v":{"description":"Vout = Vin × R2 / (R1 + R2) with no load. Unit: V.","type":"number","x-unit":"V"},"r2_ohm":{"description":"Bottom resistor (computed as R1 × Vout / (Vin − Vout) when solving). Unit: Ω.","type":"number","x-unit":"Ω"},"division_ratio":{"description":"Vout / Vin = R2 / (R1 + R2).","type":"number"},"current_ma":{"description":"I = Vin / (R1 + R2), the quiescent current drawn from the source. Unit: mA.","type":"number","x-unit":"mA"},"power_r1_w":{"description":"I² × R1. Unit: W.","type":"number","x-unit":"W"},"power_r2_w":{"description":"I² × R2. Unit: W.","type":"number","x-unit":"W"},"total_power_w":{"description":"Vin × I. Unit: W.","type":"number","x-unit":"W"},"output_impedance_ohm":{"description":"Thévenin source resistance seen by a load: R1 ∥ R2 = R1 × R2 / (R1 + R2). Unit: Ω.","type":"number","x-unit":"Ω"}}},"formula":"output_voltage_v = input_voltage_v × r2_ohm / (r1_ohm + r2_ohm); r2_ohm = r1_ohm × target_output_voltage_v / (input_voltage_v − target_output_voltage_v); current = input_voltage_v / (r1_ohm + r2_ohm); power = current² × R","method":"Unloaded divider. A load RL across R2 replaces R2 by R2 ∥ RL; keep the output impedance at least 10 × smaller than the load for less than 10 % error.","sources":[{"name":"Wikipedia – Voltage divider","url":"https://en.wikipedia.org/wiki/Voltage_divider","type":"reference","retrieved_at":"2026-09-24"},{"name":"HyperPhysics – Voltage divider","url":"http://hyperphysics.phy-astr.gsu.edu/hbase/electric/voldiv.html","type":"reference","retrieved_at":"2026-09-24"}],"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":"12 V, R1 = 10 kΩ, R2 = 4.7 kΩ","inputs":{"input_voltage_v":12,"r1_ohm":10000,"r2_ohm":4700},"expected":{"solved_for":"output_voltage_v","output_voltage_v":3.8367,"division_ratio":0.319728,"current_ma":0.8163,"power_r1_w":0.006664,"power_r2_w":0.003132,"total_power_w":0.009796,"output_impedance_ohm":3197.28},"url":"https://tttkmbb.com/api/v1/calculate/voltage-divider?input_voltage_v=12&r1_ohm=10000&r2_ohm=4700"},{"name":"9 V to 5 V with R1 = 1 kΩ","inputs":{"input_voltage_v":9,"r1_ohm":1000,"target_output_voltage_v":5},"expected":{"solved_for":"r2_ohm","r2_ohm":1250,"output_voltage_v":5,"current_ma":4,"power_r1_w":0.016,"power_r2_w":0.02},"url":"https://tttkmbb.com/api/v1/calculate/voltage-divider?input_voltage_v=9&r1_ohm=1000&target_output_voltage_v=5"}],"faq":[{"q":"Why does the voltage drop when I connect a load?","a":"The load is in parallel with R2, lowering the effective bottom resistance. Use resistors small enough that the output impedance is far below the load resistance, or add a buffer."},{"q":"Can I use a divider to power a circuit?","a":"Only for microamp loads or reference voltages; it wastes power continuously and the voltage sags with load. Use a regulator for supplies."}],"tags":["voltage divider","potential divider","resistor divider","vout","r1 r2"],"related":[{"calculator_id":"ohms-law","reason":"Voltage, current and resistance for one resistor."},{"calculator_id":"resistors-series-parallel","reason":"Equivalent resistance of the load in parallel with R2."},{"calculator_id":"led-resistor","reason":"Series resistor for an LED instead of a divider."}],"links":{"html":"https://tttkmbb.com/engineering/voltage-divider","markdown":"https://tttkmbb.com/engineering/voltage-divider.md","json":"https://tttkmbb.com/engineering/voltage-divider.json","api":"https://tttkmbb.com/api/v1/calculate/voltage-divider","schema":"https://tttkmbb.com/api/v1/calculators/voltage-divider","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:57:52Z"}