Radioactivity converter
Convert source activity between becquerels and curies.
1 Millicuries = 37 Megabecquerels
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About these units
Activity is the number of radioactive decays per second in a source. The SI unit is the becquerel, one decay per second. The older curie, roughly the activity of one gram of radium-226, is defined as exactly 3.7 × 10¹⁰ becquerels and is still used in US medicine and industry.
Activity is not dose. The gray and sievert (or rad and rem) measure the energy absorbed by a body and its biological effect; they cannot be converted from becquerels without knowing the isotope, distance, time and exposure.
Popular conversions
- Curies to Becquerels
- Becquerels to Curies
- Millicuries to Megabecquerels
- Megabecquerels to Millicuries
- Microcuries to Kilobecquerels
- Kilobecquerels to Microcuries
- Picocuries to Becquerels
- Becquerels to Picocuries
- Curies to Gigabecquerels
- Gigabecquerels to Curies
- Microcuries to Megabecquerels
- Megabecquerels to Microcuries
- Gigabecquerels to Millicuries
- Millicuries to Gigabecquerels
- Nanocuries to Becquerels
- Disintegrations per minute to Becquerels
Questions people ask
How many becquerels are in a curie?
Exactly 37 000 000 000 (3.7 × 10¹⁰) becquerels.
How many MBq is one mCi?
Exactly 37 MBq. This is the conversion used for nuclear medicine doses.
Can I convert becquerels to sieverts?
No. Becquerels count decays; sieverts measure the effect on the body, which depends on the isotope and the exposure.
Factors checked 19 October 2026.