Becquerel to Curie Converter
Convert radioactivity between becquerels and curies — Bq, kBq, MBq, GBq, TBq, Ci, mCi, µCi, nCi, pCi, dpm and rutherfords — with the same activity shown in every unit (1 Ci = 37 GBq).
How it works
1 Bq = 1 decay per second · 1 Ci = 3.7 × 10¹⁰ Bq = 37 GBq · 1 mCi = 37 MBq · 1 µCi = 37 kBq · 1 nCi = 37 Bq · 1 pCi = 0.037 Bq · 1 Bq = 60 dpm · 1 Rd = 10⁶ Bq
Activity is the number of nuclei that decay each second. The SI unit is the becquerel (Bq), one decay per second. The older curie (Ci) was defined as the activity of about one gram of radium-226 and fixed at exactly 3.7 × 10¹⁰ Bq; it is still common in US nuclear medicine and lab licensing. Activity says nothing about the energy deposited in tissue — that is the absorbed dose (gray) or equivalent dose (sievert).
Worked example
A 1 mCi source is 1 × 3.7 × 10⁷ = 37,000,000 Bq, which is 37.00 MBq. The same activity is 0.001 Ci, 1,000 µCi or 2.220 × 10⁹ disintegrations per minute.
Sources: BIPM — SI Brochure (becquerel) · NIST — Guide to the SI, units outside the SI (curie)
Frequently asked questions
How many becquerels are in a curie?
Exactly 3.7 × 10¹⁰ Bq (37 GBq). So 1 mCi = 37 MBq, 1 µCi = 37 kBq and 1 pCi = 0.037 Bq.
How do I convert MBq to mCi?
Divide by 37. A 740 MBq dose of technetium-99m is 20 mCi; 370 MBq is 10 mCi.
How do I convert pCi/L of radon to Bq/m³?
Multiply by 37: 1 pCi/L = 37 Bq/m³. The US EPA action level of 4 pCi/L is 148 Bq/m³.
Are becquerels and sieverts the same thing?
No. Becquerels count decays per second (activity). Sieverts measure the biological effect of the energy absorbed by the body (equivalent or effective dose). Converting between them needs the radionuclide, exposure route and dose coefficients.
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This calculator is for educational purposes. Double-check important results before acting on them.