Calculators

Syllabus-aligned circuit math with step-by-step working — live, offline, copy-friendly.

Ohm's Law — V = I × R

Enter any two of voltage, current or resistance. Leave the third blank to solve for it. Power (P = V × I) is computed automatically.

Voltage

Current

Resistance

Enter at least two values to compute the third.

Common trap: Current is not used up as it flows around a circuit — the same current that leaves the battery returns to it. What a resistor drops is voltage, and what the circuit converts is energy.