Curie is 3.7e10 becquerels.
Curies to Becquerels Converter — Ci to Bq
Convert Curie (Ci) to Becquerel (Bq) using the exact conversion factor (1 curie = 37,000,000,000 becquerel). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Curies to Becquerels 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.
Becquerel is one radioactive decay per second.
Result = input x 3.7e+10 / 1.
Activity units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Curies to Becquerels
Curie and Becquerel 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. Curie is typically associated with still widely used in the United States alongside the SI becquerel, while Becquerel is typically associated with universal — SI derived unit used worldwide.
Formula
becquerels = curies × 37000000000
This factor comes from each unit's defined relationship to the category's base unit: 1 curie equals 37000000000 base units, and 1 becquerel equals 1 base unit, so dividing one by the other gives the direct curie-to-becquerel factor of 37000000000.
Simple example
1 Ci × 37000000000 = 37,000,000,000 Bq
1 curie = 37,000,000,000 becquerels.
Real-world example
10 Ci × 37000000000 = 370,000,000,000 Bq
10 curies = 370,000,000,000 becquerels.
Conversion table
| Curie (Ci) | Becquerel (Bq) |
|---|---|
| 0.001 Ci | 37,000,000 Bq |
| 0.01 Ci | 370,000,000 Bq |
| 0.1 Ci | 3,700,000,000 Bq |
| 1 Ci | 37,000,000,000 Bq |
| 10 Ci | 370,000,000,000 Bq |
| 100 Ci | 3.7e+12 Bq |
Reverse conversion: Becquerel to Curie
1 Bq × 2.702703e-11 = 2.702703e-11 Ci
1 becquerel = 2.702703e-11 curies.
curies = becquerels × 2.702703e-11
For a page dedicated to this direction, see Becquerel to Curie.
Curie vs. Becquerel
| Aspect | Curie | Becquerel |
|---|---|---|
| Family | non-SI unit, still common in the US | SI derived unit |
| Typical use | Nuclear medicine dosing in the US | International radiation safety and environmental monitoring |
| Where it's used | Still widely used in the United States alongside the SI becquerel | Universal — SI derived unit used worldwide |
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.
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.
Curie — sources
- NIST — Curie (unit) — History and definition of the curie relative to the SI becquerel.
Becquerel — sources
- BIPM SI Brochure, 9th edition — Definition of the becquerel as an SI derived unit.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many becquerels are in 1 curie?
1 curie equals 37,000,000,000 becquerels, using the exact defined conversion factor rather than an estimate.
How do I convert curie to becquerel?
Multiply the curie value by 37000000000. The converter above does this instantly to whatever precision you set.
How do I convert becquerel back to curie?
Use the reverse factor: 1 becquerel equals 2.702703e-11 curies. You can also use the swap control in the converter above to flip the direction instantly.
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.
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.
Is the curie to becquerel conversion exact?
Yes. The SI derived unit of radioactive activity, equal to exactly one radioactive decay 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 curie still used today?
Still widely used in the United States alongside the SI becquerel