Magnetic Field Calculator
A long wire carrying 10 A produces 0.2 mT of magnetic flux density 1 cm away, from B = μ₀I/(2πr), about four times Earth’s field.
0.200000000108875 mT
Full answer, then cut to fewer decimals (not rounded):
- 0.200000000108875 mT
- 0.20000000010887 mT
- 0.2000000001088 mT
- 0.200000000108 mT
- 0.20000000010 mT
- 0.2000000001 mT
- 0.200000000 mT
- 0.20000000 mT
- 0.2000000 mT
- 0.200000 mT
- 0.20000 mT
- 0.2000 mT
- 0.200 mT
- 0.20 mT
- 0.2 mT
- In tesla
- 0.0002000000001 T
- In microtesla
- 200.0000001 µT
- In gauss
- 2.000000001 G
- Field strength H = B/(μ₀μᵣ)
- 159.1549431 A/m
Step-by-step solution
- B = μ₀I ÷ (2πr)
- B = 0.0002000000001 T = 0.2000000001 mT
Magnetic Field Formula
B = μ₀I/(2πr) (wire), μ₀NI/(2R) (loop centre), μ₀μᵣNI/l (solenoid)
toroid B = μ₀μᵣNI/(2πR); H = B/(μ₀μᵣ)
Worked Example
A long straight wire carrying 10 A, at 1 cm:
- B = μ₀I ÷ (2πr)
- B = 0.0002000000001 T = 0.2000000001 mT
In microtesla: 200.0000001 µT · In gauss: 2.000000001 G · Field strength H = B/(μ₀μᵣ): 159.1549431 A/m
GATE tip
Ampère’s law gives the wire, solenoid and toroid results directly; the loop needs Biot–Savart. Inside a long solenoid B is uniform, and outside it is nearly zero.
More Electromagnetic Fields Calculators
-
Inductance Calculator
L = μ₀μᵣN²A / l
toroid: l = 2πR (mean radius); coax: L/length = (μ₀/2π) ln(b/a)
Example: A 200-turn air-cored solenoid, 20 mm in diameter and 100 mm long: Inductance L = 157.914 µH.
-
Electric Field Calculator
E = q/(4πε r²), λ/(2πε r), σ/(2ε)
ε = ε₀εᵣ; potential of a point charge V = q/(4πε r)
Example: A 1 nC point charge, 1 m away, in air: Electric field |E| = 8.98755 V/m.
-
Lorentz Force Calculator
F = q v B sin θ, F = B I L sin θ
orbit radius r = mv⊥/(|q|B); cyclotron frequency f = |q|B/(2πm)
Example: An electron moving at 10⁶ m/s at right angles to a 0.5 T field: Force F = 8.01088 × 10⁻¹⁴ N.
-
Capacitance Calculator
C = ε₀εᵣA/d
coax C = 2πε L/ln(b/a); concentric spheres 4πε ab/(b − a); isolated sphere 4πε a
Example: Two 100 cm² plates 1 mm apart in air: Capacitance C = 88.5419 pF.
Frequently asked questions
What is the difference between B and H?
H (A/m) depends only on currents; B (T) includes the material: B = μ₀μᵣH. In air they differ only by μ₀.
How strong is Earth’s field?
About 25–65 µT. A fridge magnet is around 5 mT and an MRI scanner 1.5–3 T.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Magnetic Field Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/magnetic-field-calculator/
IEEE
Scientific Converters, "Magnetic Field Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/magnetic-field-calculator/