Ohm's law

⚡ Ohm's Law

The fundamental law of electrical engineering: The relationship between voltage, current, and resistance. Simple and precise calculation of all three parameters.

Available Calculations:

Ohm's Law: U = R × I

Calculate voltage, current, or resistance

Ohm's Law – The Basis of Electrical Engineering

Ohm's Law describes the linear relationship between voltage (U), current (I), and resistance (R). It forms the basis for understanding electrical circuits and is essential for all electrical calculations.

Ohm's Law
U = I × R

Calculate voltage, current, or resistance according to Ohm's Law.

U = I × R

💡 Enter the known values – leave the field you want to calculate empty.

✅ Result:

Example Calculation:
A 12 V circuit has an ohmic load with a resistance of 3 Ohm. What current results from these values?
U = I × R
I = U / R
I = 12 V / 3 Ω
I = 4 A

Units of Measurement:
Voltage U = Volt [V]
Current I = Ampere [A]
Resistance R = Ohm [Ω]

Formula

U = I × R

Changed results I = U / R and R = U / I. U is the voltage in volts, I is the current in amperes and R is the resistance in ohms (Ω). If two quantities are known, the calculator calculates the third.

What does Ohm's law say?

The strength of the electrical current flowing through an object is proportional to the electrical voltage. More precisely: If the electrical resistance - the quotient of voltage and current - is constant, i.e. independent of voltage and current, Ohm's law applies to the object. It is named after Georg Simon Ohm, who was the first to conclusively prove this connection for some simple conductors.

Calculation example

A 3 Ω ohmic consumer is connected to a 12 V circuit. Which current flows?

I = U / R
I = 12V / 3Ω
I = 4 A