Instant mCi ↔ MBq Converter
Use this tool to convert radioactive activity values between millicuries (mCi) and megabecquerels (MBq).
What this mCi to MBq calculator does
This calculator converts radioactivity values from mCi (millicurie) to MBq (megabecquerel), and also in reverse. It is useful in nuclear medicine, radiopharmacy, health physics, and academic settings where both conventional and SI units are used.
The conversion is exact and based on the standard relationship between curie and becquerel units. If you are preparing dose worksheets, checking administered activity, or reviewing literature from different regions, this quick tool helps prevent unit mistakes.
Conversion formula
MBq = mCi × 37
mCi = MBq ÷ 37
Quick reference values
| mCi | MBq |
|---|---|
| 0.5 mCi | 18.5 MBq |
| 1 mCi | 37 MBq |
| 2 mCi | 74 MBq |
| 5 mCi | 185 MBq |
| 10 mCi | 370 MBq |
| 20 mCi | 740 MBq |
Worked examples
Example 1: Convert 3.2 mCi to MBq
Multiply by 37:
3.2 × 37 = 118.4 MBq
Example 2: Convert 555 MBq to mCi
Divide by 37:
555 ÷ 37 = 15 mCi
Why these units both appear in practice
- mCi is common in older references and in some clinical workflows.
- MBq is the SI-based unit and is widely used internationally.
- Clinical protocols, package inserts, and scanner software may show one or both units.
- Consistent conversion helps avoid underdosing or overdosing due to unit confusion.
Tips for accurate activity conversion
- Always write the unit next to every value in notes and labels.
- Double-check decimal placement before administration.
- For very small or very large values, use scientific notation when needed.
- When documenting, round according to your institutional policy.
FAQ
Is 1 mCi exactly 37 MBq?
Yes. The relationship is exact by definition from the curie-to-becquerel conversion.
Can I use this for all radionuclides?
Yes for unit conversion itself. The factor is universal for activity units. However, clinical dose recommendations still depend on the specific radionuclide and indication.
Does this include decay correction?
No. This tool only converts units at a single point in time. Decay correction requires half-life and time elapsed.