Magnetic Field Converter
Same value in every unit
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Tesla and gauss: a factor of ten thousand
One tesla is exactly 10,000 gauss. The tesla is the SI unit and is used in physics and medicine; the gauss is the older CGS unit and survives in magnet catalogues, gaussmeters and a great deal of engineering practice. Nothing separates them but convention.
What the numbers feel like
- 25–65 µT (0.25–0.65 G) — the Earth's field, what a compass follows
- 5 mT (50 G) — the face of a fridge magnet
- 0.1–1 T — a loudspeaker magnet gap
- 1.5–3 T — a clinical MRI scanner
- 10+ T — research superconducting magnets
Why distance matters so much
Field strength falls away very steeply as you move from a magnet — much faster than intuition suggests. A magnet that grips hard against steel does almost nothing a few centimetres away, which is why "how strong is this magnet" is not really a question with one answer.
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Frequently Asked Questions
Between about 25 and 65 microtesla depending on where you are — 0.25 to 0.65 gauss. That is what a compass responds to, and it is roughly a hundred thousand times weaker than an MRI magnet.
Exactly ten thousand. The gauss is the CGS unit and the tesla the SI one; physics and medicine use tesla, while magnet manufacturers and older instruments still quote gauss.
Commonly 1.5 or 3 tesla, which is 15,000 or 30,000 gauss. The reason the safety rules around MRI rooms are so strict is that a field that strong turns any loose steel object into a projectile.
About 5 millitesla, or 50 gauss, right at its surface — around a hundred times the Earth's field but a three-hundredth of an MRI. Field strength falls very steeply with distance, which is why it holds a note but not a spanner.
No.