Magnetic Field Conversion Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/10/2026
To convert a magnetic field, use the relationship 1 tesla = 10,000 gauss. Example: a 1.5 tesla medical MRI corresponds to a field of 15,000 gauss.
Explanation
The tesla (T), the SI unit of magnetic flux density, coexists in everyday use with the gauss (G), an older CGS unit still widely used, notably in geomagnetism (Earth's magnetic field, very weak, is more conveniently expressed in gauss or nanoteslas) and in the documentation of many magnets and devices. The relationship between the two is fixed: 1 tesla equals exactly 10,000 gauss, a factor that follows directly from the definition of the two unit systems. The tesla itself is a fairly large unit for everyday use: Earth's magnetic field at the surface is only about 0.25 to 0.65 gauss depending on latitude (25 to 65 microteslas), while a common refrigerator magnet reaches a few hundred gauss, and a medical MRI typically uses a field of 1.5 to 3 teslas (15,000 to 30,000 gauss), tens of thousands of times more intense than Earth's field. To calculate a magnetic field from an electric current and a geometry rather than converting a known value, see our solenoid magnetic field calculator.
Example: a 1.5 tesla medical MRI
Inputs
Value: 1.5. Starting unit: tesla. Target unit: gauss.
Calculation
1 tesla = 10,000 gauss, so 1.5 tesla = 1.5 × 10,000 = 15,000 gauss.
Result
A magnetic field of 1.5 tesla equals 15,000 gauss.
Frequently asked questions
Why is the gauss still used when the tesla is the official SI unit?
Because the gauss remains firmly entrenched in some historical and practical uses, notably in geomagnetism (where the very small values to be measured stay more readable in gauss or nanoteslas than in teslas) and in the documentation of many commercial permanent magnets, particularly in the United States.
Is Earth's magnetic field really that weak?
Yes, about 25 to 65 microteslas (0.25 to 0.65 gauss) depending on latitude, a field tens of thousands of times weaker than a medical MRI. It is precisely this weakness that makes a compass sensitive to disturbances from nearby magnets or electronic devices, whose local field far exceeds Earth's faint one.
How do you calculate the magnetic field generated by an electric current?
This calculator converts a known magnetic field value between units; to calculate the field generated by an electric current in a wire or a coil, see our solenoid magnetic field calculator and straight wire magnetic field calculator.