Choose two electrical quantities, enter measurements in V, A, mA, Ω, kΩ, W or mW, and solve an ideal resistive circuit.
01 / KNOWN QUANTITIES
02 / INPUT VALUES
For a DC or purely resistive circuit. Enter up to six decimal places; mA, kΩ and mW are converted to A, Ω and W before solving. Some zero pairs have no finite answer.
03 / YOUR RESULT
04 / FORMULA
Voltage in volts, current in amperes, resistance in ohms and power in watts. These ideal formulas do not model AC phase, temperature or non-ohmic components.
All electrical calculations stay in your browser.
Enter the values you want to compare; processing happens in your browser.
Adjust optional settings and review validation feedback before relying on the estimate.
Review the formulas and equivalent values, then copy the result you need.
Select any pair of voltage, current, resistance and power. Enter nonnegative values with the correct units, then review the four calculated quantities and formulas.
Six two-quantity combinations, unit conversions and explicit validation of indeterminate zero cases. Designed for simple DC or purely resistive circuits.
Electrical inputs and results stay in browser memory. Nothing is uploaded or stored.
For an ideal resistive circuit, voltage V equals current I times resistance R. Power P equals voltage times current.
Choose any two of voltage, current, resistance and power: V+I, V+R, V+P, I+R, I+P or R+P.
Yes. The calculator converts milliamperes to amperes, kilo-ohms to ohms and milliwatts to watts before calculating.
Some zero pairs require division by zero or do not uniquely determine resistance or current. These cases show an error instead of an infinite or misleading answer.
No. The formulas assume simple DC or purely resistive loads and do not model AC phase, reactive impedance or changing temperature.
No. Measurements and calculations stay in your browser; nothing is uploaded or saved.