Magnetic Field Converter

Convert between tesla, millitesla, microtesla, and gauss — for magnets, MRI, physics, and geomagnetic measurements.

Magnetic Field

T, mT, Gauss

From

Result

1000

1 T = 1000 mT

Popular conversions

What Is a Magnetic Field Converter?

A magnetic field converter translates magnetic flux density between units — tesla to gauss, millitesla to microtesla. Magnetic flux density (often just called magnetic field) measures the strength of a magnetic field, and the SI unit is the tesla (T). The older CGS unit, the gauss (G), is still widely used: one tesla equals exactly 10,000 gauss, a factor that comes up constantly.

This converter routes through the tesla using exact factors. Magnetic fields span an enormous range — the Earth's field is tens of microtesla, a fridge magnet a few millitesla, and an MRI scanner several tesla — so prefixes and the tesla-gauss bridge are both essential. Enter a value in any unit and read it across tesla, millitesla, microtesla, and gauss.

This is one category of the full Unit Converter — pair it with our percentage calculator or scientific calculator for related everyday maths.

How Magnetic Field Conversion Works

Everything routes through the tesla

Each unit has a fixed tesla factor. The converter normalises to tesla, then projects to millitesla, microtesla, and gauss.

1 tesla = 10,000 gauss

The tesla (SI) and gauss (CGS) differ by exactly 10⁴. This is the single most-used magnetic-field conversion.

Prefixes scale by 1,000

1 T = 1,000 mT = 1,000,000 µT. The Earth's field (~50 µT) and an MRI (~3 T) sit far apart on this scale.

Flux density vs flux

Tesla measures flux density (per area); the weber measures total flux. The converter handles flux density (field strength).

Core Magnetic Field Conversion Factors

Multiply to reach tesla; divide to come back. The gauss factor is exactly 10,000.

Tesla → gauss

× 10000

One tesla is exactly 10,000 gauss. The SI–CGS magnetic bridge.

T → mT

× 1000

One tesla is 1,000 millitesla. Strong permanent magnets sit in the mT-to-T range.

mT → µT

× 1000

One millitesla is 1,000 microtesla. The Earth's field is tens of microtesla.

How to Use the Magnetic Field Converter

1
Enter the field value
Type the magnetic field strength you want to convert — a magnet rating, an instrument reading, a field measurement.
2
Choose the 'from' unit
Pick tesla, millitesla, microtesla, or gauss as your starting unit.
3
Choose the 'to' unit
Select the target unit, or swap the two to reverse direction.
4
Read every unit at once
The all-units table shows the field across T, mT, µT, and gauss together.

Key Magnetic Field Concepts

Tesla

The SI unit of magnetic flux density. Strong: an MRI runs at 1.5–3 T, while the Earth's field is just tens of microtesla.

Gauss

The CGS unit, equal to 10⁻⁴ tesla. Common for permanent-magnet ratings and instruments — a fridge magnet is a few hundred to a few thousand gauss.

Magnetic flux density

Field strength per unit area, measured in tesla or gauss. Distinct from total magnetic flux, measured in webers.

Wide natural range

Earth's field ~50 µT, sunspots ~0.3 T, MRI ~3 T, the strongest lab magnets ~45 T — prefixes keep this span readable.

Real-World Magnetic Field Conversions

🧲

Fridge magnet

A fridge magnet is roughly 5 mT (50 gauss). Permanent-magnet strength is quoted in mT or gauss.

🏥

MRI scanner

A clinical MRI runs at 1.5 or 3 T — that's 15,000 or 30,000 gauss. Medical imaging works in tesla.

🌍

Earth's field

The geomagnetic field is about 25–65 µT (0.25–0.65 gauss). Compasses and magnetometers measure in microtesla.

🔬

Lab electromagnets

Research magnets reach 10–45 T (100,000–450,000 gauss). Physics labs push the tesla scale to its limits.

🔊

Speaker magnets

A neodymium speaker magnet is around 1.2 T (12,000 gauss). Strong rare-earth magnets are rated in tesla and gauss.

🧭

Magnetometers

A sensor reading 50 µT detects the Earth's field; mapping anomalies converts µT to nanotesla for fine detail.

Best Practices for Magnetic Field Conversion

✓Remember 1 T = 10,000 gauss. The tesla-gauss factor is exactly 10⁴. It's the most common magnetic conversion and easy to misplace by powers of ten.
✓Carry the prefix carefully. T, mT, and µT differ by factors of 1,000. The Earth's field (µT) and an MRI (T) are six orders of magnitude apart.
✓Distinguish flux density from flux. Tesla and gauss measure flux density (per area); total flux is in webers. Don't convert one as if it were the other.
✓Match the unit to the field. Magnet specs and instruments often use gauss; SI physics and MRI use tesla. Convert to the convention your context expects.
✓Mind safety near strong fields. Multi-tesla MRI and lab magnets pose real hazards to metal objects and implants. Unit conversion is the easy part; respect the field strength.

Common Magnetic Field Conversion Mistakes

Misplacing the gauss factor

1 T = 10,000 gauss, not 1,000 or 100,000. Getting the 10⁴ factor wrong throws magnet ratings off by powers of ten.

Dropping a metric prefix

Reading µT as mT, or mT as T, shifts the field 1,000-fold — confusing the Earth's field with a strong magnet.

Confusing flux density with flux

Tesla (flux density) and weber (total flux) are different quantities. The converter handles field strength, not total flux.

Ignoring field direction

Magnetic field is a vector. The converter changes units of magnitude; orientation and gradient are separate considerations.

Why Magnetic Field Conversion Matters

Magnetic field strength matters for magnets, motors, medical imaging, geophysics, and physics research — and it's split between the SI tesla and the still-common CGS gauss, with an exact 10,000:1 ratio that's easy to misplace. Add the huge dynamic range from the Earth's microtesla field to an MRI's several tesla, and prefix discipline becomes essential.

Whether reading a magnet datasheet in gauss, an MRI spec in tesla, or a magnetometer in microtesla, getting the unit right is the basis for any field calculation or comparison. A converter that routes through the tesla and surfaces mT, µT, and gauss together keeps engineers, clinicians, and scientists aligned across both systems.

Built for physicists, magnet and motor engineers, MRI technologists, and geophysicists converting between tesla, gauss, and their prefixes.

Linear unit factors follow the BIPM SI brochure, the NIST Guide to the SI, and ISO 80000. Currency rates load live from open.er-api.com; crypto prices from CoinGecko. See our methodology and editorial policy. Educational only — not certified for regulated trading, settlement, medical, or aerospace use.

Magnetic Field Converter FAQs

Multiply tesla by 10,000 to get gauss, since one tesla equals exactly 10⁴ gauss. So a 1.5 T MRI is 15,000 gauss, and a 5 mT fridge magnet is 50 gauss. To go from gauss to tesla, divide by 10,000.

The tesla (T) is the SI unit of magnetic flux density, measuring the strength of a magnetic field. It's a large unit: the Earth's field is only tens of microtesla, while an MRI scanner reaches 1.5 to 3 tesla. One tesla equals one weber per square metre, or 10,000 gauss.

They measure the same thing — magnetic flux density — in different systems. The tesla is the SI unit; the gauss is the older CGS unit. One tesla equals exactly 10,000 gauss. Magnet datasheets and many instruments still use gauss, while physics and medical imaging use tesla.

The Earth's magnetic field ranges from about 25 to 65 microtesla (0.25 to 0.65 gauss) depending on location, strongest near the poles. That's tiny compared with a fridge magnet (~5 mT) or an MRI (1.5–3 T), which is why magnetometers measure in microtesla or even nanotesla.

Flux density (tesla or gauss) is the field strength per unit area. Total magnetic flux (the weber) is the field integrated over an area. So tesla = weber per square metre. This converter handles flux density — the field strength you measure at a point — not total flux.

It uses exact definitions (1 T = 10,000 gauss = 1,000 mT = 10⁶ µT) and routes every conversion through the tesla at full precision, so the result is exact to your input precision.