Electricity & Magnetism
Magnetic Flux
Magnetic flux through a surface.
Variables
ΦBWb
Magnetic flux
Flux through surface
In SI units: kg·m²/(A·s²)
BT
Magnetic field
Field strength
In SI units: kg/(A·s²)
Am²
Area
Loop area
Allowed values: greater than 0
θ°
Angle
Between B and normal
In SI units: rad
Derivation
Φ = ∫B·dA. For uniform field: Φ = BA cos θ.
Your notes
0/5000
Check value
Round inputs run through this page's calculator. Use it to test your own working or a rearranged form. It is a test case, not a real-world example.
- B = 2 T (Magnetic field)
- A = 3 m² (Area)
- θ = 4 ° (Angle)
Result: ΦB = 5.9853843 Wb
Other electricity & magnetism formulas with the same quantities
- Motional EMF (Electromagnetic Induction) shares Magnetic field
- Magnetic Force on Charge (Magnetism) shares Magnetic field
- Magnetic Force on Wire (Magnetism) shares Magnetic field
- Magnetic Field (Long Wire) (Magnetism) shares Magnetic field
- Magnetic Field (Solenoid) (Magnetism) shares Magnetic field
- Energy Density (Magnetic Field) (Magnetism) shares Magnetic field
Where this formula is listed
- Electricity & Magnetism formulas, under Electromagnetic Induction, alongside Self-Inductance, Inductor Energy, RL Time Constant, Mutual Inductance EMF and Transformer Equation.
- In the electricity & magnetism list it comes after Faraday's Law and before Motional EMF.
- Electricity & Magnetism formula sheet, one of 48 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Magnetic Flux formula?
Magnetic Flux is written Φ_B = BA cos θ. Magnetic flux through a surface. It belongs to Electricity & Magnetism, under Electromagnetic Induction.
What are the units in Φ_B = BA cos θ?
In SI units, Φ_B is magnetic flux, measured in kg·m²/(A·s²); B is magnetic field, measured in kg/(A·s²); A is area, measured in m²; θ is angle, measured in rad.
How is the Magnetic Flux formula derived?
Φ = ∫B·dA. For uniform field: Φ = BA cos θ. The result is Φ_B = BA cos θ.