How to read the converter
Enter an activity and choose its source and target units. The converted value updates as you type.
1 mCi = 37 MBq exactly
The becquerel is the SI unit of activity. The curie is a non-SI unit with an exact relation to the becquerel.
To convert mCi to MBq, multiply by 37. To convert MBq to mCi, divide by 37.
0.027 is a rounded form of 1/37; this converter uses the exact ratio.
Conversion tables
| mCi | MBq |
|---|---|
| 0.1 | 3.7 |
| 0.5 | 18.5 |
| 1 | 37 |
| 2 | 74 |
| 5 | 185 |
| 10 | 370 |
| 20 | 740 |
| 50 | 1850 |
| 100 | 3700 |
| 1000 | 37000 |
| MBq | mCi |
|---|---|
| 1 | 0.027027 |
| 10 | 0.27027 |
| 37 | 1 |
| 100 | 2.7027 |
| 370 | 10 |
| 1000 | 27.027 |
| Unit | Name | Value in Bq |
|---|---|---|
| Ci | curie | 3.7 × 10^10 |
| mCi | millicurie | 3.7 × 10^7 |
| µCi | microcurie | 37000 |
| nCi | nanocurie | 37 |
| pCi | picocurie | 0.037 |
| Bq | becquerel | 1 |
| kBq | kilobecquerel | 1000 |
| MBq | megabecquerel | 1 × 10^6 |
| GBq | gigabecquerel | 1 × 10^9 |
| TBq | terabecquerel | 1 × 10^12 |
MBq is not mBq
MBq is the megabecquerel (10^6 Bq). The millibecquerel, mBq (10^−3 Bq), is a billion times smaller; prefix symbols are case-sensitive in the SI: upper case for multiples such as M (mega), lower case for submultiples such as m (milli).
The microcurie symbol is µCi; ‘uCi’ is an informal typed substitute.
Activity versus radiation dose
Activity is measured in Bq or Ci; it is not absorbed dose (Gy) or dose equivalent (Sv).
Frequently asked questions
How many MBq are in a mCi?
1 mCi = 37 MBq exactly.
How do I convert MBq to mCi?
Divide the value in MBq by 37. For example, 37 MBq = 1 mCi.
Is MBq the same as mBq?
No. MBq means megabecquerel, 10^6 Bq. mBq means millibecquerel, 10^−3 Bq. One MBq is one billion mBq.
How many becquerels are in a curie?
1 Ci = 3.7 × 10^10 Bq exactly.
Can I convert mCi to mSv?
No. Millicuries measure activity; millisieverts are used for dose equivalent. These are different quantities, so there is no unit-conversion factor between them.
Why does a chart say 0.027?
It is a rounded form of 1/37. One MBq equals 1/37 mCi, or 0.027027… mCi.
References
- Bureau International des Poids et Mesures. The International System of Units (SI), 9th edition 2019, V4.01 (June 2026). Appendix 1: 12th CGPM (1964) Resolution 7; Table 7, SI prefixes. doi:10.59161/AUEZ1291.
- Thompson A, Taylor BN. Guide for the Use of the International System of Units (SI). NIST Special Publication 811, Appendix B.9. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b9.
- 10 CFR § 20.1005 Units of radioactivity. Electronic Code of Federal Regulations, current to 3 November 2026. https://www.ecfr.gov/current/title-10/section-20.1005.