Activity Calculator (Becquerel/Curie)

A Becquerel is the SI unit of radioactivity. One Becquerel equals exactly one radioactive disintegration (nuclear decay event) per second. It replaced the older Curie as the standard scientific unit of activity.

The Curie is the traditional (non-SI) unit of radioactivity, originally defined as the activity of one gram of radium-226. One Curie equals 3.7 × 10¹⁰ disintegrations per second, which is exactly 37 gigabecquerels (GBq). It is still widely used in medical and industrial settings in the United States.

To convert Becquerel to Curie, divide the Bq value by 3.7 × 10¹⁰ (37,000,000,000). For example, 1,000 Bq = 1,000 / 37,000,000,000 ≈ 2.703 × 10⁻⁸ Ci. Alternatively, multiply by 2.7027 × 10⁻¹¹.

A Megabecquerel equals one million Becquerels (10⁶ Bq). MBq is a commonly used unit in nuclear medicine — for example, administered doses of radiopharmaceuticals are typically expressed in MBq. One MBq equals approximately 0.027 millicuries (mCi).

dpm stands for disintegrations per minute. Since one Becquerel is one disintegration per second, 1 Bq equals exactly 60 dpm. The dpm unit is commonly used in liquid scintillation counting and environmental radiation monitoring.

A Picocurie is one trillionth of a Curie (10⁻¹² Ci), equal to 0.037 disintegrations per second or about 2.22 dpm. It is most commonly used to express low-level radioactivity concentrations, such as radon gas in air (measured in pCi/L) or naturally occurring radioactive materials in water and soil.

Different units evolved for different fields and eras. The Curie was developed early in nuclear science and remains common in medical and industrial contexts in the US, while the Becquerel is the modern SI unit used internationally. Prefixed versions (mCi, MBq, kBq, pCi) exist to express the enormous range of radioactivity levels encountered — from tiny environmental traces to large medical or industrial sources.

Yes. Since 1 Ci = 37 GBq, it follows that 1 mCi = 37 MBq exactly. This is a standard conversion equivalence widely cited by organizations such as the US Department of Health and Human Services (HHS/REMM) and used in nuclear medicine dosing.