Becquerel Curie Radiation Unit Converter
Convert becquerel-family and curie-family activity units from the same NIST basis. Enter the activity value, choose the source and target units, and the result window plus summary cards update immediately.
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Read becquerels and curies from the same activity value
This converter rewrites radioactive activity between the becquerel family and the curie family. The becquerel is the SI unit: 1 Bq means one nuclear disintegration per second. The curie is a much larger legacy unit, still seen in medical, industrial, and research material as mCi or μCi.
Use the left window for the value and units shown in your source, then choose the unit you need on the right. Bq, kBq, MBq, GBq, TBq and Ci, mCi, μCi, nCi, pCi are all calculated from the same relationship, so the summary cards help catch prefix mistakes before you copy a result.
Use it in screen order
- Enter the activity value first. For example, enter 37 when converting 37 GBq to Ci.
- Choose the source unit exactly as it appears in the report or label. A missing prefix can change the value by a factor of 1000.
- Choose the target unit you want to compare or copy. Use Switch units when you need the reverse direction.
- Copy the result with both the original unit and the converted unit, especially for safety notes or lab documentation.
Units and basis
- Bq means becquerel. 1 Bq is one disintegration per second.
- kBq, MBq, GBq, and TBq are 10³, 10⁶, 10⁹, and 10¹² Bq.
- Ci means curie. NIST and SI guidance list 1 Ci = 3.7 × 10¹⁰ Bq.
- mCi, μCi, nCi, and pCi are 10⁻³, 10⁻⁶, 10⁻⁹, and 10⁻¹² Ci.
Example conversions
The two unit families differ by a large factor, so it helps to keep an intermediate prefix in view.
Rounding and cautions
- This page converts activity units only. Absorbed dose, equivalent dose, and biological effect use separate units such as Gy and Sv.
- Real handling decisions also depend on radionuclide, half-life, shielding, distance, and time.
- Do not drop the prefix when recording a value. MBq and GBq, or mCi and μCi, are very different quantities.
- For very large or very small values, keep scientific notation next to the rounded number to avoid digit-count mistakes.
FAQ
How many becquerels are in one curie?
1 Ci is 3.7 × 10¹⁰ Bq, or 37 GBq. Because curie is large, many practical documents use mCi, μCi, nCi, or pCi.
What do becquerel and curie measure?
Both measure radioactive activity, the rate of nuclear disintegrations. 1 Bq is one disintegration per second, while 1 Ci is 3.7 × 10¹⁰ Bq.
Are activity units the same as radiation dose units?
No. Bq and Ci describe how active a source is. Dose to people or material is expressed with other units such as gray (Gy) or sievert (Sv).
Why do medical notes show both mCi and MBq?
Some countries and institutions still use mCi while others use SI units such as MBq. To compare them, use 1 mCi = 37 MBq.
Why does the result sometimes use scientific notation?
Bq and Ci are far apart in scale. For example, 1 Bq is about 2.7027×10^-11 Ci, so scientific notation is easier to read than a long decimal.
References used
The conversion table follows NIST SP 811 Appendix B.9 and NIST SP 330 Appendix 1 for the relationship between becquerel and curie.