Ohm’s Law & DC Circuit Power Calculator
Solve voltage, current, resistance, and power relations, analyze series/parallel networks, and design LED dropping resistors
Calculated Circuit Power & Resistance
30.00 W • 4.80 Ω
Power: 30,000 mW (0.030 kW) • Resistance: 4.800 Ω
Electromotive Force (Voltage)
12.000 V
12,000 mV • 0.012 kV
Current Intensity (Amperage)
2.500 A
2,500 mA • 2.50 × 10⁶ µA
Ohmic Resistance (Impedance)
4.800 Ω
0.0048 kΩ • 4,800 mΩ
Dissipated Power (Wattage)
30.000 W
0.0402 Horsepower (HP)
Source potential difference
Individual Branch Resistors (Ω)
Enter 0 to omit
Enter 0 to omit
Equivalent Network Resistance (R_eq)
790.00 Ω
Total Current: 30.38 mA • Total Power: 729.11 mW
Branch R₁ Analysis
V₁: 3.04 V • I₁: 30.38 mA
P₁: 92.29 mW
Branch R₂ Analysis
V₂: 6.68 V • I₂: 30.38 mA
P₂: 203.04 mW
Branch R₃ Analysis
V₃: 14.28 V • I₃: 30.38 mA
P₃: 433.78 mW
Branch R₄ Analysis
Disabled (0 Ω)
Not included in network
e.g. 5V USB, 9V Battery, 12V Rail
Standard indicator: 15–20 mA
Connected cathode-to-anode
Standard Resistor Recommendation
510 Ω (E24)
Exact Calculated Value: 490.00 Ω
Resistor Power Dissipation
196.0 mW (0.196 W)
P = V_R × I_f
Minimum Wattage Rating
1/2 Watt (0.5 W)
Includes 2× engineering safety margin
Voltage Dropped by Resistor
9.80 V
81.7% of source voltage
Actual Current with Standard R
19.22 mA
-3.9% deviation from target