Curie to Becquerel Converter (Ci ⇄ Bq)
Convert radioactivity from curies (Ci) to becquerels (Bq) and back. Supports mCi, µCi, kBq, MBq, GBq. Includes formula, examples, and reference table for nuclear medicine and radiation protection.
Conversion inputs
Enter a value in Ci or Bq, choose the scaling, and the converter follows the exact definition of 1 Ci = 3.7 × 10¹⁰ Bq.
Ci and Bq values refresh together after every calculation.
How to Use This Converter
Type an activity value in curies or becquerels, select the unit scaling for each side, and click Calculate. The other field updates with the exact equivalent using 1 Ci = 3.7 × 10¹⁰ Bq.
Methodology
The tool tracks the standardized base unit (Ci or Bq) and applies scale factors whenever the unit dropdown changes. Decimal precision and exponential formatting ensure conversions are deterministic and reversible.
- Curie inputs convert to base Ci, then multiply by 3.7 × 10¹⁰ to build the becquerel result before applying the destination scale.
- Becquerel inputs undo the factor by dividing by 3.7 × 10¹⁰ and scaling to the requested curie unit.
- Every displayed value preserves the selected unit so you can copy it directly into reports without guessing multipliers.
Quick Ci → Bq table
| Ci | Bq | MBq |
|---|
Rounded for readability.
Important note
These are unit conversions only. For patient administration, workplace limits, transport, or waste classification, follow your regulator (IAEA, ICRP, national authority) and medical physics team.
Why convert between curie and becquerel?
Older documents, U.S. procedures, or legacy nuclear instrumentation still quote activity in curies or millicuries. Modern international standards, EU directives, and most scientific journals expect becquerels or multiples (kBq, MBq, GBq). A precise converter keeps your reports consistent.
Typical values
- Small lab sources (check): tens of kBq to a few MBq
- Nuclear medicine diagnostic doses: some hundred MBq (varies with radionuclide)
- Industrial sources: GBq and above
FAQ
1. What is the smallest unit I can enter?
You can enter down to nCi on the left side, or directly in Bq on the right side. The calculator will scale up or down.
2. Can I get pCi (picocurie)?
pCi is common in environmental monitoring (water, air). To convert pCi/L → Bq/m³ you usually need an extra step for volume. This page focuses on activity only.
3. Are these factors exact?
Yes, the exact definition is 1 Ci = 3.7 × 10¹⁰ Bq. We use this in the calculations.
Full original guide (expanded)
Related nuclear/radiation tools
Good practices
- ✔ Always state the reference date/time
- ✔ Specify radionuclide (Tc-99m, I-131, etc.)
- ✔ Keep units consistent across the report
- ✔ Follow your local radiation safety officer