What the converter covers
The calculator converts activity normalized by mass, volume or area. Mass-specific activity — becquerel and curie per unit mass (Bq/kg, Bq/g, Ci/kg, mCi/g, nCi/g, pCi/g). Volumetric activity — per unit volume (Bq/L, Bq/mL, Bq/m³, µCi/mL). Surface contamination — per unit area (Bq/m², Bq/cm², dpm/cm²).
Quantities are not interchangeable
Conversion is performed only within a single quantity. Mass-specific, volumetric and surface activity cannot be converted into one another without material density or source geometry, so the calculator never mixes these quantities. Factors are exact: 1 Ci = 3.7·10¹⁰ Bq, with metric mass, volume and area relations.
Typical use cases
The tool helps with sample specific-activity control (Bq/kg), volumetric activity of water and air (Bq/L, Bq/m³) and surface radioactive contamination (Bq/cm², dpm/cm²).
Frequently asked questions
What does Bq/kg (Bq/L) mean?
Bq/kg is becquerels per kilogram: the number of decays per second in 1 kg of material. Bq/L is the same per litre, used for water and other liquids. For building materials the effective specific activity Aeff is regulated (class I — up to 370 Bq/kg under NRB-99/2009); a separate calculator computes it.
How do I convert Bq/kg to pCi/g?
1 Bq/kg = 0.027027 pCi/g, and conversely 1 pCi/g = 37 Bq/kg. The converter uses the exact relation 1 Ci = 3.7·10¹⁰ Bq and shows the result in mass, volume and surface units at once.
What is the difference between specific and volumetric activity?
Specific (mass) activity refers to the sample mass (Bq/kg, Bq/g), volumetric activity to the volume (Bq/L, Bq/m³) and surface activity to the area (Bq/cm², dpm/cm²). Converting between mass and volume needs the material density.
Where can I find the specific activity of a pure nuclide?
In the specific activity table: it is computed from the half-life and mass number per ENDF/B-VIII.0 for every nuclide and lists Bq/g and Ci/g.
