How this conversion works
Activity is the number of radioactive decays per second. One becquerel is one decay per second.
The curie is defined as exactly 3.7 × 10¹⁰ Bq, so 1 pCi = 0.037 Bq.
Formula: result = value × (base units per source unit) ÷ (base units per target unit)
Where this conversion is used
- Radon test results in pCi/L compared with Bq/m³ limits.
- Nuclear medicine doses in mCi or MBq.
- Laboratory source activity in µCi or kBq.
Worked example: 4 pCi to becquerels
- 1 pCi = 0.037 Bq.
- 4 × 0.037 = 0.148 Bq.
Unit definitions
| Unit | In becquerels | Note |
|---|---|---|
| Becquerel (Bq) | 1 | One decay per second. |
| Kilobecquerel (kBq) | 1,000 | |
| Megabecquerel (MBq) | 1,000,000 | |
| Gigabecquerel (GBq) | 1,000,000,000 | |
| Terabecquerel (TBq) | 1,000,000,000,000 | |
| Curie (Ci) | 37,000,000,000 | 3.7 × 10¹⁰ Bq exactly. |
| Millicurie (mCi) | 37,000,000 | |
| Microcurie (µCi) | 37,000 | |
| Nanocurie (nCi) | 37 | |
| Picocurie (pCi) | 0.037 | |
| Rutherford (Rd) | 1,000,000 | |
| Disintegrations per minute (dpm) | 0.0166666667 |
Picocuries to becquerels
| Picocurie (pCi) | Becquerel (Bq) |
|---|---|
| 1 | 0.037 |
| 2 | 0.074 |
| 4 | 0.148 |
| 10 | 0.37 |
| 100 | 3.7 |
Becquerels to picocuries
| Becquerel (Bq) | Picocurie (pCi) |
|---|---|
| 1 | 27.027 |
| 37 | 1,000 |
| 100 | 2,702.7027 |
| 148 | 4,000 |
| 1,000 | 27,027.027 |
Millicuries to megabecquerels
| Millicurie (mCi) | Megabecquerel (MBq) |
|---|---|
| 1 | 37 |
| 5 | 185 |
| 10 | 370 |
| 20 | 740 |
| 30 | 1,110 |
Things to watch for
- Radon guidance in the US is commonly given in pCi/L, and elsewhere in Bq/m³. Convert concentration by converting the activity part (pCi → Bq) and the volume part (L → m³) separately: 1 pCi/L = 37 Bq/m³.
Precision and sources
Results are calculated from the definitions above and rounded to 12 significant digits; the converter shows up to eight decimal places and the tables four. Reference: NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B.
Frequently asked questions
Is activity the same as dose?
No. Activity counts decays at the source. Dose depends on the radiation type, energy, distance, shielding and time of exposure.