Radiation-Activity Converter
Convert radioactivity (the rate of nuclear decay) between becquerels, curies, rutherfords and other SI and historic units.
Written by Rahman · Last reviewed
Quick answer
Radioactivity measures decays per second. The SI unit is the becquerel, defined as one decay per second. One curie is 3.7 × 10¹⁰ becquerels (originally the activity of a gram of radium-226), which makes the curie an enormous unit, so medical quantities are normally quoted in megabecquerels or millicuries.
| Becquerel (Bq) | 1 |
| Kilobecquerel (kBq) | 0.001 |
| Megabecquerel (MBq) | 0.000001 |
| Gigabecquerel (GBq) | 1.000000e-9 |
| Curie (Ci) | 2.702703e-11 |
| Millicurie (mCi) | 2.702703e-8 |
| Microcurie (µCi) | 0.00002702702703 |
| Rutherford (Rd) | 0.000001 |
About the Radiation-Activity Converter
Radioactivity, or activity, measures how many atomic nuclei decay per second in a radioactive sample. The SI unit is the becquerel; the curie is the older unit.
It is used in nuclear medicine, research and radiation safety.
Frequently Asked Questions
What is a becquerel?
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A becquerel is one nuclear decay per second, the SI unit of radioactivity.
How many becquerels are in a curie?
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One curie equals 3.7 × 10¹⁰ becquerels, the activity of about one gram of radium.
What does activity tell you?
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Activity indicates how radioactive a sample is, but not the biological effect. That also depends on the radiation type and energy.