Centigray is 0.01 gray units.
Centigrays to Grays Converter — cGy to Gy
Convert Centigray (cGy) to Gray (Gy) using the exact conversion factor (1 centigray = 0.01 gray). See the formula, worked examples, conversion table, history, and common uses.
Centigrays to Grays 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.
Gray is absorbed dose in joules per kilogram.
Result = input x 0.01 / 1.
Absorbed Dose units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Centigrays to Grays
Centigray and Gray 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. Specifically: Centigray is 0.01 gray units, and gray is absorbed dose in joules per kilogram.
Formula
grays = centigrays × 0.01
This factor comes from each unit's defined relationship to the category's base unit: 1 centigray equals 0.01 base units, and 1 gray equals 1 base unit, so dividing one by the other gives the direct centigray-to-gray factor of 0.01.
Simple example
1 cGy × 0.01 = 0.01 Gy
1 centigray = 0.01 grays.
Real-world example
10 cGy × 0.01 = 0.1 Gy
10 centigrays = 0.1 grays.
Conversion table
| Centigray (cGy) | Gray (Gy) |
|---|---|
| 0.001 cGy | 0.00001 Gy |
| 0.01 cGy | 0.0001 Gy |
| 0.1 cGy | 0.001 Gy |
| 1 cGy | 0.01 Gy |
| 10 cGy | 0.1 Gy |
| 100 cGy | 1 Gy |
Reverse conversion: Gray to Centigray
0.01 Gy × 100 = 1 cGy
0.01 grays = 1 centigray.
centigrays = grays × 100
For a page dedicated to this direction, see Gray to Centigray.
Understanding the Centigray (cGy)
Centigray is 0.01 gray units.
Understanding the Gray
Gray (Gy) measures absorbed radiation dose. The SI derived unit of absorbed radiation dose, equal to one joule of radiation energy absorbed per kilogram of matter. It is classified as a SI derived unit.
Where it's used: Universal — SI derived unit used worldwide in medicine and radiation protection
Gray vs. sievert. The gray measures physically absorbed energy; the sievert measures equivalent dose, which weights the gray value for how biologically damaging a given type of radiation is. The same absorbed dose in gray can correspond to different sievert values depending on the radiation type.
Uses of the Gray today
- Radiation therapy dose prescriptions in medicine
- Radiation safety and occupational dose monitoring
- Nuclear and radiological research
History of the Gray
The gray is named after Louis Harold Gray (1905–1965), a British physicist who pioneered the physics of radiation dosimetry and its biological effects, and was adopted by the CGPM as an SI derived unit in 1975.
Historical origin. Gray was not the invention of a single named person; it developed through the process described above.
Gray — sources
- BIPM SI Brochure, 9th edition — Official definition of the gray as an SI derived unit.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many grays are in 1 centigray?
1 centigray equals 0.01 grays, using the exact defined conversion factor rather than an estimate.
How do I convert centigray to gray?
Multiply the centigray value by 0.01. The converter above does this instantly to whatever precision you set.
How do I convert gray back to centigray?
Use the reverse factor: 1 gray equals 100 centigrays. You can also use the swap control in the converter above to flip the direction instantly.
What is a centigray?
Centigray (cGy) is a unit of radiation.
What is a gray?
Gray (Gy) measures absorbed radiation dose. The SI derived unit of absorbed radiation dose, equal to one joule of radiation energy absorbed per kilogram of matter. It is classified as a SI derived unit.
Is the centigray to gray conversion exact?
Yes. Both centigray and gray are defined by fixed standards rather than physical artifacts, so the factor of 0.01 used above is exact to as many digits as you choose to display.
What is the difference between gray vs. sievert?
The gray measures physically absorbed energy; the sievert measures equivalent dose, which weights the gray value for how biologically damaging a given type of radiation is. The same absorbed dose in gray can correspond to different sievert values depending on the radiation type.