Bq → Ci
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The Bq to Ci converter translates radioactivity measurements from becquerels (Bq) to curies (Ci). The becquerel is the SI unit, while the curie is a historical unit still used in nuclear medicine and environmental studies. The formula Ci = Bq ÷ 3.7 × 10¹⁰ is based on the curie's definition as 37 billion disintegrations per second.
Use this tool when comparing radioactivity data between SI standards and curies. Applications include scientific reports, environmental risk assessments, and dosimetry calculations. The 3.7 × 10¹⁰ factor originates from the curie's historical basis in radium-226 decay. This conversion helps contextualize values in scales more intuitive for specific fields.
Be cautious when interpreting results: the curie is significantly larger than the becquerel, which can lead to misunderstandings with small numbers. Always confirm input data is in Bq and verify calculation accuracy for critical measurements. Consult technical standards or experts for precise applications where errors could have significant consequences.
Frequently asked questions
Why does the Bq to Ci conversion use 3.7 × 10¹⁰?
The curie was historically defined as the activity of 1 gram of radium-226, which equals 3.7 × 10¹⁰ disintegrations per second. This became the standard conversion factor between the units.
Are there other units for measuring radioactivity?
Yes, besides Bq and Ci, units like microcurie (µCi) and gigabecquerel (GBq) exist for smaller or larger values. The choice depends on the measurement context.
Does this calculator convert Ci to Bq as well?
To convert Ci to Bq, multiply the Ci value by 3.7 × 10¹⁰. This inverse calculation can be performed using the same formula in reverse.
When should I use this calculator in environmental studies?
Use it when comparing natural or industrial radioactivity data with international standards that reference both unit systems.