Ohm’s Law Calculator
Enter any two values and click Calculate. Leave the value you want computed blank.
Formula: V = I × R. (Voltage = Current × Resistance)Ohm’s Law Calculator Online – Calculate Voltage, Current, Resistance & Power
Intro
Ohm’s Law is one of the most important principles in electrical engineering and electronics. It describes the relationship between voltage (V), current (I), and resistance (R) in a circuit. For students, electricians, and engineers, manually solving these equations can be time-consuming. That’s why an Ohm’s Law Calculator online is incredibly useful.
The Ohm’s Law Calculator helps you quickly find any missing value—voltage, current, resistance, or power—when you know the other parameters. It eliminates errors, saves time, and is perfect for both learning and professional applications.
Formula / Working
Ohm’s Law and power formulas form the basis of this calculator:
- Ohm’s Law:
V=I×RV = I \times RV=I×R
Where:
- VVV = Voltage (volts)
- III = Current (amps)
- RRR = Resistance (ohms)
- Rearranging the formula:
- I=VRI = \frac{V}{R}I=RV
- R=VIR = \frac{V}{I}R=IV
- Power formula:
P=V×IP = V \times IP=V×I
Or expressed differently:
- P=I2×RP = I^2 \times RP=I2×R
- P=V2RP = \frac{V^2}{R}P=RV2
The calculator uses these formulas to compute the correct value instantly.
Step-by-Step Usage
Using the Ohm’s Law Calculator online is very simple:
- Enter two known values (e.g., voltage and resistance).
- Select the units (volts, ohms, amps, watts).
- Click “Calculate.”
- The tool will instantly display the missing values for voltage, current, resistance, and power.
Examples
Example 1 – Finding Current
- Voltage = 12V
- Resistance = 6Ω
I=VR=126=2AI = \frac{V}{R} = \frac{12}{6} = 2AI=RV=612=2A
Power = P=V×I=12×2=24WP = V \times I = 12 \times 2 = 24WP=V×I=12×2=24W
Result: Current = 2A, Power = 24W
Example 2 – Finding Resistance
- Voltage = 120V
- Current = 10A
R=VI=12010=12ΩR = \frac{V}{I} = \frac{120}{10} = 12ΩR=IV=10120=12Ω
Power = P=V×I=120×10=1200WP = V \times I = 120 \times 10 = 1200WP=V×I=120×10=1200W
Result: Resistance = 12Ω, Power = 1200W
Example 3 – Finding Voltage
- Current = 0.5A
- Resistance = 200Ω
V=I×R=0.5×200=100VV = I \times R = 0.5 \times 200 = 100VV=I×R=0.5×200=100V
Power = P=V×I=100×0.5=50WP = V \times I = 100 \times 0.5 = 50WP=V×I=100×0.5=50W
Result: Voltage = 100V, Power = 50W
FAQs
1. What is Ohm’s Law used for?
It’s used to calculate the relationship between voltage, current, and resistance in electrical circuits.
2. Can this calculator find power too?
Yes, it also calculates electrical power using the formulas P=V×IP = V \times IP=V×I, P=I2×RP = I^2 \times RP=I2×R, or P=V2RP = \frac{V^2}{R}P=RV2.
3. Do I need advanced electrical knowledge to use it?
No, you just enter two known values, and the calculator solves the rest.
4. Is this useful for students?
Absolutely. It’s a great learning aid for physics and electrical engineering students.
5. Can I use this for AC circuits?
Yes, but remember that Ohm’s Law applies directly to DC or the resistive component of AC circuits. For AC with reactance, you’ll need advanced formulas.