Becquerel is one radioactive decay per second.
Becquerels to Curies Converter — Bq to Ci
Convert Becquerel (Bq) to Curie (Ci) using the exact conversion factor (1 becquerel = 2.702703e-11 curie). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Becquerels to Curies converter
Converter
Radiation Converter
Convert radioactivity, absorbed dose, and equivalent dose units by compatible radiation family.
Context values
Some unit families need one extra value for a physically accurate result.
Curie is 3.7e10 becquerels.
Result = input x 1 / 3.7e+10.
Activity units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Becquerels to Curies
Becquerel and Curie both belong to the radiation-measurement family, though radiation quantities fall into genuinely distinct categories: absorbed dose (gray, rad) measures energy deposited in matter, equivalent dose (sievert, rem) weights that for biological harm, and activity (becquerel, curie) measures how often a radioactive source decays — this page only converts between units of the same kind. Becquerel is typically associated with universal — SI derived unit used worldwide, while Curie is typically associated with still widely used in the United States alongside the SI becquerel.
Formula
curies = becquerels × 2.702703e-11
This factor comes from each unit's defined relationship to the category's base unit: 1 becquerel equals 1 base unit, and 1 curie equals 37000000000 base units, so dividing one by the other gives the direct becquerel-to-curie factor of 2.702703e-11.
Simple example
1 Bq × 2.702703e-11 = 2.702703e-11 Ci
1 becquerel = 2.702703e-11 curies.
Real-world example
10 Bq × 2.702703e-11 = 2.702703e-10 Ci
10 becquerels = 2.702703e-10 curies.
Conversion table
| Becquerel (Bq) | Curie (Ci) |
|---|---|
| 0.001 Bq | 2.702703e-14 Ci |
| 0.01 Bq | 2.702703e-13 Ci |
| 0.1 Bq | 2.702703e-12 Ci |
| 1 Bq | 2.702703e-11 Ci |
| 10 Bq | 2.702703e-10 Ci |
| 100 Bq | 2.702703e-9 Ci |
Reverse conversion: Curie to Becquerel
2.702703e-11 Ci × 37000000000 = 1.00000011 Bq
2.702703e-11 curies = 1.00000011 becquerels.
becquerels = curies × 37000000000
For a page dedicated to this direction, see Curie to Becquerel.
Becquerel vs. Curie
| Aspect | Becquerel | Curie |
|---|---|---|
| Family | SI derived unit | non-SI unit, still common in the US |
| Typical use | International radiation safety and environmental monitoring | Nuclear medicine dosing in the US |
| Where it's used | Universal — SI derived unit used worldwide | Still widely used in the United States alongside the SI becquerel |
Understanding the Becquerel
Becquerel (Bq) measures radioactivity (activity). The SI derived unit of radioactive activity, equal to exactly one radioactive decay per second. It is classified as a SI derived unit.
Where it's used: Universal — SI derived unit used worldwide
Uses of the Becquerel today
- International radiation safety and environmental monitoring
- Nuclear medicine dosing outside the US
- Food and water radioactivity contamination limits
History of the Becquerel
The becquerel is named after Henri Becquerel (1852–1908), the French physicist who discovered radioactivity in 1896 when he found that uranium salts emitted radiation spontaneously, without any external energy source — sharing the 1903 Nobel Prize in Physics with Marie and Pierre Curie for this work.
Historical origin. Becquerel was not the invention of a single named person; it developed through the process described above.
Understanding the Curie
Curie (Ci) measures radioactivity (activity). Originally based on the activity of one gram of radium-226; now fixed at exactly 3.7 × 10¹⁰ decays per second. It is classified as a non-SI unit, still common in the US.
Where it's used: Still widely used in the United States alongside the SI becquerel
Curie vs. becquerel. Both measure radioactive activity (decays per second), but the becquerel is the modern SI unit (1 decay/second) while the curie is the older, much larger unit (37 billion decays/second) still common in US medical and regulatory contexts.
Uses of the Curie today
- Nuclear medicine dosing in the US
- Radioactive source labeling
- Historical and US regulatory radiation-activity reporting
History of the Curie
The curie is named after Marie Curie (1867–1934) and Pierre Curie (1859–1906), the physicists who coined the term 'radioactivity,' discovered the elements polonium and radium, and won the 1903 Nobel Prize in Physics for their research — Marie Curie later won a second Nobel Prize, in Chemistry, in 1911.
Historical origin. Curie was not the invention of a single named person; it developed through the process described above.
Becquerel — sources
- BIPM SI Brochure, 9th edition — Definition of the becquerel as an SI derived unit.
Curie — sources
- NIST — Curie (unit) — History and definition of the curie relative to the SI becquerel.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many curies are in 1 becquerel?
1 becquerel equals 2.702703e-11 curies, using the exact defined conversion factor rather than an estimate.
How do I convert becquerel to curie?
Multiply the becquerel value by 2.702703e-11. The converter above does this instantly to whatever precision you set.
How do I convert curie back to becquerel?
Use the reverse factor: 1 curie equals 37,000,000,000 becquerels. You can also use the swap control in the converter above to flip the direction instantly.
What is a becquerel?
Becquerel (Bq) measures radioactivity (activity). The SI derived unit of radioactive activity, equal to exactly one radioactive decay per second. It is classified as a SI derived unit.
What is a curie?
Curie (Ci) measures radioactivity (activity). Originally based on the activity of one gram of radium-226; now fixed at exactly 3.7 × 10¹⁰ decays per second. It is classified as a non-SI unit, still common in the US.
Is the becquerel to curie conversion exact?
Yes. Originally based on the activity of one gram of radium-226; now fixed at exactly 3.7 × 10¹⁰ decays per second. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between curie vs. becquerel?
Both measure radioactive activity (decays per second), but the becquerel is the modern SI unit (1 decay/second) while the curie is the older, much larger unit (37 billion decays/second) still common in US medical and regulatory contexts.
Where is the becquerel still used today?
Universal — SI derived unit used worldwide