Magnetic Field Current Carrying Wire Calculator
Calculate the magnetic field strength around a straight current-carrying wire using Ampère's law
Calculate Magnetic Field Strength
Electric current flowing through the wire
Perpendicular distance from the wire
Magnetic Field Results
Alternative Units
Tesla: 0.000e+0 T
Gauss: 0.000e+0 G
Microtesla: 0.000e+0 μT
Earth Comparison
Earth's field: ~5×10⁻⁵ T
Ratio to Earth: 0.00e+0×
Weaker than Earth's field
Formula used: B = (μ₀ × I) / (2π × d)
Permeability of free space: μ₀ = 4π × 10⁻⁷ T⋅m/A
Input values: I = 0.000 A, d = 0.000 m
Field Strength Analysis
Example Calculation
Household Wire Example
Scenario: Standard household electrical wire
Current: 15 A (typical household circuit)
Distance: 1 cm from the wire
Safety consideration: Calculate magnetic field exposure
Calculation
B = (μ₀ × I) / (2π × d)
B = (4π × 10⁻⁷ × 15) / (2π × 0.01)
B = (1.885 × 10⁻⁵) / (0.0628)
B = 3.00 × 10⁻⁴ T = 300 μT
This is about 6 times stronger than Earth's magnetic field
Magnetic Field Properties
Direction
Forms concentric circles around the wire
Use right-hand rule to determine direction
Strength
Inversely proportional to distance
Directly proportional to current
Reference
Earth's field: ~50 μT
MRI machine: ~1-3 T
Unit Conversions
Understanding Magnetic Fields from Current-Carrying Wires
Ampère's Circuital Law
When electric current flows through a straight wire, it creates a magnetic field that forms concentric circles around the wire. This phenomenon is described by Ampère's circuital law, one of Maxwell's fundamental equations of electromagnetism.
The Right-Hand Rule
- •Point your right thumb in the direction of current flow
- •Your fingers curl in the direction of the magnetic field
- •Field lines form circular loops around the wire
- •Field strength decreases with distance from wire
Formula Derivation
B = (μ₀ × I) / (2π × d)
B: Magnetic field strength (Tesla)
μ₀: Permeability of free space (4π × 10⁻⁷ T⋅m/A)
I: Current through the wire (Amperes)
d: Distance from the wire (meters)
Key Assumptions
- •Wire is infinitely long and straight
- •Current is uniformly distributed
- •Medium is non-magnetic (air or vacuum)
Real-World Applications
⚡ Power Lines
Calculate magnetic field exposure near high-voltage transmission lines for safety assessments.
🔧 Electric Motors
Design electromagnetic devices by understanding field strength around current-carrying conductors.
🏥 Medical Devices
Ensure electromagnetic compatibility and safety in medical equipment design.