Magnetic Field Converter
Convert between tesla, millitesla, microtesla and gauss.
Results update as you type.
How it works
A magnetic field converter restates a magnetic flux density in a different unit, moving between the SI tesla and its millitesla and microtesla subdivisions, and the older gauss from the centimetre-gram-second system. It reduces your figure to tesla, the SI unit for magnetic flux density, then scales out to the unit you choose, so one mechanism covers MRI scanner ratings, magnet specifications, Earth's field measurements and physics coursework alike. This matters because magnetism is described in two coexisting systems whose numbers differ by a factor of ten thousand. Medical and engineering work usually uses tesla — an MRI scanner is quoted as 1.5 or 3 tesla — while much laboratory equipment, older physics texts and consumer magnet specifications use gauss. Earth's magnetic field is a small fraction of a gauss, more naturally written in microtesla. Reading a magnet rated in gauss against a scanner rated in tesla, or a compass sensor spec in microtesla, is only possible once every figure shares one unit. The convert-through-tesla method is used because every field unit has a fixed ratio to the tesla — one gauss is exactly one ten-thousandth of a tesla, one millitesla is a thousandth, one microtesla a millionth — so pivoting through it keeps results exact and needs only one factor per unit. Physicists, electrical and biomedical engineers, MRI technicians and students all rely on a magnetic field converter whenever a flux-density figure arrives in an unfamiliar unit.
Convert to tesla via known factors, then to the target unit
The input is multiplied by its unit's fixed number of tesla to express the field in tesla, then divided by the target unit's tesla value to complete the conversion. The metric prefixes milli and micro are exact powers of ten below the tesla, and one gauss is defined as exactly 1e-4 tesla, so every unit has a fixed ratio to the SI base, making the pivot exact for every pairing with one stored factor per unit.
Source:International System of Units (SI) — NIST
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter value, from and to.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Converted magnetic field updates instantly as you type — no button to press.
Frequently asked questions
How do I convert tesla to gauss?
Multiply the tesla figure by 10,000, since one tesla equals exactly ten thousand gauss. So a 1.5 tesla MRI scanner produces a field of 15,000 gauss. To reverse it, divide gauss by 10,000. The relationship is exact by definition, as the gauss is the centimetre-gram-second counterpart to the SI tesla, so only display rounding appears in the converted result.
How strong is Earth's magnetic field?
Earth's magnetic field at the surface is roughly 25 to 65 microtesla, or about 0.25 to 0.65 gauss, depending on location. That is tens of thousands of times weaker than an MRI scanner. Because the value is small, it is often expressed in microtesla or nanotesla for convenience. Compass and smartphone magnetometer sensors are calibrated to detect this weak field for navigation.
What is a tesla?
The tesla is the SI unit of magnetic flux density, named after inventor Nikola Tesla, defined as one weber of magnetic flux per square metre. It is a large unit: fridge magnets are a few hundredths of a tesla, medical MRI scanners are 1.5 to 3 tesla, and the strongest research magnets exceed 40 tesla. Everyday magnetic fields are therefore often quoted in milli- or microtesla.
Is gauss still used today?
Yes, gauss remains common in some laboratory instruments, magnet product specifications and older physics literature, even though the tesla is the official SI unit. Handheld gaussmeters and many consumer magnet listings still report in gauss. Because one tesla is ten thousand gauss, converting between the two is a frequent need when comparing legacy or product figures against modern SI-based specifications.
Why convert magnetic field through tesla?
The tesla is the SI unit for magnetic flux density, so every other field unit has a fixed, exactly defined ratio to it. Using it as the pivot means the converter needs only one factor per unit rather than a separate rule for each pair, keeps results exact, and matches the unit that electromagnetism equations expect, which makes cross-checking laboratory and engineering calculations straightforward and reliable.