03 // Bidirectional STEM Calculators // PHYSICSV = I × R

Ohm's Law Voltage, Current & Resistance Calculator

Ohm's Law states that the electrostatic potential difference V across an ideal conductor is directly proportional to the current I flowing through it and its electrical resistance R: V = I × R.

V = I × R

Pick which value you want to calculate (or type into any field):Solving for: V — Voltage (Potential Difference)

Voltage (Potential Difference)Calculated

Electromotive potential across the load in Volts

0.11,000.00

Electric Current

Charge flow rate in Amperes

0.001100

Electrical Resistance

Conductor or load resistance in Ohms

0.1100,000.00

Calculated Result · Voltage (Potential Difference) (V)

12V

Converted units:

Step-by-Step Calculation

01Canonical Law: V = I × R

02Given Inputs (Base Units): I = 0.5 A, R = 24 Ω

03Solve for V (Voltage (Potential Difference)): V = 12 V

Ohm's Law states that the electrostatic potential difference V across an ideal conductor is directly proportional to the current I flowing through it and its electrical resistance R: V = I × R.

Real-World Reference Values

USB-C PD Standard Rail5V / 9V / 15V / 20V

Up to 5A (100W) or 48V 5A (240W EPR)

Automotive DC Bus12.6V – 14.4V

Lead-acid / LiFePO4 starter & accessory rail

Logic CMOS Pull-Up10 kΩ @ 3.3V → 0.33 mA

Low quiescent digital bus termination

20-Row Comparison Table

Voltage (Potential Difference) (V) · Electric Current (I)

Compare across:

Ohm's Law Voltage, Current & Resistance Calculator — Electric Current → Voltage (Potential Difference)
#	Electric Current (A)	Voltage (Potential Difference) (V)	Δ %
01	0.001 A	0.024 V	-99.80%
02	0.5 ACurrent	12 V	0.00%
03	1.5009 A	36.0211 V	+200.18%
04	2.2508 A	54.0197 V	+350.16%
05	3.0008 A	72.0183 V	+500.15%
06	3.7507 A	90.0168 V	+650.14%
07	4.5006 A	108.0154 V	+800.13%
08	5.2506 A	126.0139 V	+950.12%
09	6.0005 A	144.0125 V	+1100.10%
10	6.7505 A	162.0111 V	+1250.09%
11	7.5004 A	180.0096 V	+1400.08%
12	8.2503 A	198.0082 V	+1550.07%
13	9.0003 A	216.0068 V	+1700.06%
14	9.7502 A	234.0053 V	+1850.04%
15	10.5002 A	252.0039 V	+2000.03%
16	11.2501 A	270.0024 V	+2150.02%
17	12 A	288.001 V	+2300.01%
18	12.75 A	305.9996 V	+2450.00%
19	13.4999 A	323.9981 V	+2599.98%
20	14.2499 A	341.9967 V	+2749.97%

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Frequently Asked Questions

How do I use kΩ or mA in Ohm's Law without manual conversion?+

Use the inline unit dropdown next to I or R to select Milliamperes (mA) or Kilohms (kΩ). The engine converts to base SI Amperes and Ohms automatically.

Does Ohm's Law apply to AC circuits?+

Yes, when resistance R is generalized to complex impedance Z (V = I × Z) accounting for inductive and capacitive reactance.

How do I compute power dissipated in the resistor?+

Combine Ohm's Law with Joule heating: P = V × I = I² × R = V² / R.