Radioactivity Converter

What the Radioactivity Converter does

Radioactivity Converter: 1 Bq = 2.702703e-11 Ci, so multiply a becquerel value by 2.702703e-11 to get curie, or divide to go back. Example: 1 Bq = 2.702703e-11 Ci.

Feed it Value, From and To; it hands back Result, How it was calculated and Reverse conversion. Change any input and the output follows immediately.

Unit mistakes are quietly expensive. They have wrecked spacecraft and ruined recipes alike. That is usually what brings students converting units for homework here.

The work is done by JavaScript already loaded in your browser, so your input never crosses the network.

Below the tool you will find the field reference, the method, and an example computed from the values it opens with.

What do the Radioactivity Converter fields mean?

The Radioactivity Converter uses 3 inputs. Because the form arrives filled, the first useful result costs you zero typing.

How does the Radioactivity Converter work?

Both units are converted through radioactivity's base unit (Bq), so any of the 8 units in the dropdowns can be paired in either direction without loss of accuracy.

Exact definitions are preferred throughout: the metre, the inch and the pound all have them. Only where a unit depends on a measured constant is an accepted published value substituted.

Worked example

These are the values the Radioactivity Converter loads by default, and the result it produces from them. Open the tool above and you will find precisely these figures already in place.

Radioactivity: becquerels and curies

1 curie (Ci) equals exactly 3.7 × 10¹⁰ becquerels (Bq). The curie was originally based on the radioactivity of 1 gram of radium-226, while the becquerel, the modern SI unit, is defined simply as 1 radioactive decay per second, making it a vastly smaller unit by comparison.

Worth knowing

• Because the becquerel is so much smaller than the curie, everyday radioactivity measurements in becquerels often involve very large numbers (thousands, millions, or more), which is one reason the curie persisted in some regulatory and medical contexts even after the SI officially adopted the becquerel.
• US regulatory and medical documents still frequently use the curie (and its sub-units, like the millicurie used in nuclear medicine dosing), while most international scientific literature has moved to the becquerel: a split similar to several imperial/metric divides elsewhere on this site, just for a much more specialised unit.
• Radioactivity (measured here) is a distinct concept from radiation dose (covered in the absorbed-dose and equivalent-dose converters). This unit describes how many atoms are decaying per second in a source, not how much biological or material effect that radiation has.

Definitions: BIPM SI Brochure · NIST reference on units

How to use it

1. Type Value.
2. Pick a value for From: the options are Becquerel (Bq), Kilobecquerel (kBq), Megabecquerel (MBq), Gigabecquerel (GBq), Curie (Ci) or Millicurie (mCi).
3. Pick a value for To: the options are Becquerel (Bq), Kilobecquerel (kBq), Megabecquerel (MBq), Gigabecquerel (GBq), Curie (Ci) or Millicurie (mCi).
4. The answer follows your cursor, in effect. Change a field and read the new figure.
5. Look at Result, How it was calculated and Reverse conversion in the output panel.
6. Use Copy Link if you want the same setup again later, or Print for a paper copy.

What this tool does not do

• Factors use the internationally agreed definitions; some industries round them differently.
• Repeated conversions compound rounding, so convert once from the original value where you can.
• Where a standard has revisions, the version used is the one named in the method section.
• Nothing here can catch a correct number entered in the wrong field.

Frequently asked questions

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