Unit converter
Radioactivity.
Convert Ci to Bq, or pick any of the 7 units in the menus. Type in either box and the other follows. Decays per second. Activity is not dose — how much radiation is being emitted says nothing on its own about the harm to a person.
| Ci | Bq |
|---|---|
| 1 Ci | 3.7×10¹⁰ Bq |
| 2 Ci | 7.4×10¹⁰ Bq |
| 3 Ci | 1.11×10¹¹ Bq |
| 4 Ci | 1.48×10¹¹ Bq |
| 5 Ci | 1.85×10¹¹ Bq |
| 10 Ci | 3.7×10¹¹ Bq |
| 15 Ci | 5.55×10¹¹ Bq |
| 20 Ci | 7.4×10¹¹ Bq |
| 25 Ci | 9.25×10¹¹ Bq |
| 50 Ci | 1.85×10¹² Bq |
| 75 Ci | 2.775×10¹² Bq |
| 100 Ci | 3.7×10¹² Bq |
| 250 Ci | 9.25×10¹² Bq |
| 500 Ci | 1.85×10¹³ Bq |
| 1000 Ci | 3.7×10¹³ Bq |
- Every unit in the menus is defined against Bq, so any pairing converts by the same single route.
Definitions
- The curie is 3.7×10¹⁰ Bq, originally the activity of a gram of radium. It is a very large unit; laboratory sources are usually microcuries.
- The becquerel is one nuclear decay per second — the SI unit of activity. It says nothing about the dose a person receives.
- Activity counts nuclear decays per second. It is not radiation dose, which depends on absorbed energy and biological effect.
- Every unit in the menus is exact by definition, so the only rounding on this page is the one you choose for the display.
How it works
Every value is converted into becquerels and then back out into the unit you asked for. One route covers every pairing in the menus, so an unusual combination is no less accurate than a common one, and adding a unit affects only that unit.
Both boxes are live. Whichever one you last typed in is the source, changing either menu recalculates straight away, and Swap exchanges the units and the values so the number you are reading stays where you are looking.
Display precision limits significant figures rather than decimal places, because one fixed number of decimals is useless across a range this wide. Very large and very small results switch to scientific notation with a proper superscript exponent. The editable box always holds a plain number at full working precision, so you can carry on from either side.
Common questions this answers: how many becquerels in a curie (3.7×10¹⁰), how many curies in a becquerel (2.7027×10⁻¹¹), and what 1 Ci is in becquerels (3.7×10¹⁰ Bq).
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